Display device

ABSTRACT

A display device includes: a pixel array having pixels arranged in matrix and having a first side parallel to a row and a second side opposite to the first side; scanning lines arranged in each row of the pixel array to supply a scanning signal to the pixels arranged in a corresponding row; signal lines arranged in each column of the pixel array to supply an image signal to the pixels arranged in a corresponding column; drive electrodes arranged in a column of the pixel array and to which a drive signal to detect an external proximate object is supplied; and a first drive electrode circuit arranged along the first side and connected to control lines and the drive electrodes arranged in the pixel array to supply the drive signal to, among the drive electrodes, the drive electrode specified by a selection signal supplied via the control lines.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Japanese Priority PatentApplication JP 2015-044976 filed in the Japan Patent Office on Mar. 6,2015, the entire content of which is hereby incorporated by reference.

BACKGROUND

The present invention relates to a display device, and in particular,relates to a display device with a touch detection function capable ofdetecting an external proximity object.

In recent years, a touch detection device referred to as a touch panelcapable of detecting an external proximity object has attractedattention. The touch panel is mounted on or integrated with a displaydevice, for example, a liquid crystal display device. In a displaydevice in which a touch panel is mounted on or integrated with a displaydevice, that is, a display device with a touch detection function,various button images or the like are displayed on the display device,and proximity of an external object to a button image is detectedthrough the touch panel. This enables the use of the touch panel asinformation input means instead of a normal mechanical button. Sincesuch a display device with a touch detection function does notnecessarily need information input means such as a keyboard or a mouse,its use tends to increase with the inclusion of mobile informationterminals such as mobile phones in addition to computers.

As a detection method of a touch detection device, some methods such asan optical type, a resistance type and a capacitance type are known.Among these types, a capacitance type touch detection device has arelatively simple structure and consumes less power and so is used formobile information terminals and the like. Japanese Patent ApplicationLaid-Open Publication No. 2012-230657 (Patent Document 1) describes acapacitance type touch detection device.

Further, in the display device, the increase in size of a displaysurface has been more and more demanded. Correspondingly, the increasein size of the touch panel has also been demanded. On the other hand,the increase in size of the display device itself is not desirablebecause portability thereof is degraded. Thus, in order to achieve theincrease in size of the display surface while suppressing the increasein size of the display device, a narrower edge frame of the displaydevice is needed. Namely, the reduction in width of an edge framesurrounding the display surface of the display device has been demanded.

SUMMARY

In a capacitance type touch detection device, for example, proximity ofan external object is detected by utilizing the change in thecapacitance value at an intersecting portion where a drive electrode anda detection electrode intersect due to the proximity (including contact)of an external object such as a finger as described in PatentDocument 1. Namely, proximity of an external object is detected based ona detection signal generated in the detection electrode when a drivesignal is supplied to the drive electrode. In a touch detection device,a plurality of drive electrodes and a plurality of detection electrodesare provided, and the plurality of drive electrodes are sequentiallyarranged in a column direction and the plurality of detection electrodesare sequentially arranged in a row direction so as to intersect with theplurality of drive electrodes.

A circuit that forms a drive signal is formed in a region correspondingto the edge frame. When a region corresponding to the edge frame is madenarrower so as to achieve the reduction in width of the edge frame, theregion allocated to the circuit that forms a drive signal becomesnarrower, and the driving ability of the circuit is degraded. When thedriving ability is degraded, the voltage change of the drive electrodebecomes slower and there arises a fear of deterioration ofcharacteristics concerning the touch detection.

An object of the present invention is to provide a display device with atouch detection function capable of preventing the deterioration ofcharacteristics of touch detection while suppressing the increase of theedge frame.

A display device according to an embodiment of the present inventionincludes: a pixel array including a plurality of pixels arranged in amatrix form and having a first side parallel to a row and a second sideopposite to the first side; a plurality of scanning lines arranged ineach row of the pixel array to supply a scanning signal to the pluralityof pixels arranged in a corresponding row; a plurality of signal linesarranged in each column of the pixel array to supply an image signal tothe plurality of pixels arranged in a corresponding column; a pluralityof drive electrodes which are arranged in a column of the pixel arrayand to which a drive signal to detect an external proximate object issupplied; and a first drive electrode circuit which is arranged alongthe first side of the pixel array and connected to a plurality ofcontrol lines and the plurality of drive electrodes arranged in thepixel array and supplies the drive signal to, among the plurality ofdrive electrodes, the drive electrode specified by a selection signalsupplied via the plurality of control lines.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing the configuration of a liquid crystaldisplay device with a touch detection function according to the firstembodiment;

FIG. 2A to FIG. 2C are explanatory views for describing the basicprinciple of capacitance type touch detection (mutual capacitance type);

FIG. 3A and FIG. 3B are a plan view and a sectional view showing anoverview of a module mounted with the liquid crystal display device witha touch detection function according to the first embodiment;

FIG. 4A to FIG. 4C are a sectional view and plan views showing anoverview of the module mounted with the liquid crystal display devicewith a touch detection function according to the first embodiment;

FIG. 5 is a plan view showing a configuration of the module mounted withthe liquid crystal display device with a touch detection functionaccording to the first embodiment;

FIG. 6 is a circuit diagram showing the configuration of a pixel arrayaccording to the first embodiment;

FIG. 7 is a block diagram showing the configuration of the liquidcrystal display device with a touch detection function according to thefirst embodiment;

FIG. 8 is a circuit diagram showing the configuration of the liquidcrystal display device with a touch detection function according to thefirst embodiment;

FIG. 9A to FIG. 9E are waveform charts showing an operation of theliquid crystal display device with a touch detection function accordingto the first embodiment;

FIG. 10 is a block diagram showing the configuration of the liquidcrystal display device with a touch detection function according to thesecond embodiment;

FIG. 11 is a circuit diagram showing the configuration of the liquidcrystal display device with a touch detection function according to thesecond embodiment;

FIG. 12A to FIG. 12E are waveform charts showing an operation of theliquid crystal display device with a touch detection function accordingto the second embodiment;

FIG. 13 is a block diagram showing the configuration of the liquidcrystal display device with a touch detection function according to thethird embodiment;

FIG. 14 is a circuit diagram showing the configuration of the liquidcrystal display device with a touch detection function according to thethird embodiment; and

FIG. 15A to FIG. 15E are waveform charts showing an operation of theliquid crystal display device with a touch detection function accordingto the third embodiment.

DETAILED DESCRIPTION

Hereinafter, each embodiment of the present invention will be describedwith reference to the drawings. However, the disclosure is only by wayof example and inventions that can easily be anticipated by personsskilled in the art by making appropriate alterations without deviatingfrom the spirit of the invention are naturally included in the scope ofthe present invention. Some drawings are shown schematically concerningthe width, thickness, shape or the like of each portion when comparedwith an actual mode for the purpose of making the description clearlyunderstood, but are provided only by way of example and do not intend tolimit the interpretation of the present invention.

In this specification and each drawing, the same reference charactersare attached to elements similar to those described in previous drawingsand a detailed description thereof may be omitted.

In the following description, a liquid crystal display device with atouch detection function is taken as an example of a display device witha touch detection function. However, each embodiment is not limited tothis and can also be applied to an OLED display device with a touchdetection function. As described above, various methods are present as atouch detection method, and an example in which the capacitance type isadopted as the touch detection method will be described below. Further,there are a plurality of types of touch detection devices that adopt thecapacitance type touch detection method, and a touch detection deviceusing the mutual capacitance type touch detection method will bedescribed as an example.

Further, in this specification, an example in which a touch detectiondevice is applied to an in-cell type liquid crystal display device witha touch detection function integrated with a display device will bedescribed. Here, the in-cell type liquid crystal display device with atouch detection function means a liquid crystal display device with atouch detection function in which at least one of the drive electrodeand the detection electrode included in the touch detection device isprovided between a pair of substrates opposed via the liquid crystal ofthe display device. Specifically, the case in which the drive electrodeincluded in the touch detection device is used also as the driveelectrode that drives the liquid crystal will be described. Since thedrive electrode is commonly used as a drive electrode for touchdetection and as a drive electrode for liquid crystal display, the driveelectrode may be referred to also as a common electrode in the followingdescription.

First Embodiment

<Basic Principle of Capacitance Type Touch Detection (Mutual CapacitanceType)>

First, the basic principle of mutual capacitance type will be described.FIG. 2A to FIG. 2C are schematic diagrams showing the basic principle ofthe capacitance type touch detection adopted in the first to thirdembodiments described below. In FIG. 2A, each of TL(0) to TL(p) is acommon electrode provided in a liquid crystal panel and each of RL(0) toRL(p) is a detection electrode provided in a touch detection panel unit.In FIG. 2A, each of the common electrodes TL(0) to TL(p) extends in acolumn direction and is arranged in parallel in a row direction. Also,each of the detection electrodes RL(0) to RL(p) extends in the rowdirection so as to intersect with the common electrodes TL(0) to TL(p)and is arranged in parallel in the column direction. The detectionelectrodes RL(0) to RL(p) are formed above the common electrodes TL(0)to TL(p) so that a gap is present between the detection electrodes RL(0)to RL(p) and the common electrodes TL(0) to TL(p).

In FIG. 2A, each of 12-0 to 12-p schematically shows a unit driveelectrode driver. In FIG. 2A, the drive signals Tx(0) to Tx(p) areoutput from the unit drive electrode drivers 12-0 to 12-p, respectively.Also, each of 13-0 to 13-p schematically shows a unit amplifier. In FIG.2A, a pulse signal encircled by a solid line shows the waveform of thedrive signal Tx(i). In FIG. 2A, a finger FG is shown as an externalobject.

In the example of FIG. 2, a pulse signal is supplied as the drive signalTx(2) to the common electrode TL(2) from the unit drive electrode driver12-2. By supplying the drive signal Tx(2) serving as a pulse signal tothe common electrode TL(2), as shown in FIG. 2B, an electric field isgenerated between the common electrode TL(2) and the detection electrodeRL(n) intersecting with the common electrode TL(2). If the finger FGtouches a position near the common electrode TL(2) of the liquid crystalpanel at this time, an electric field is generated also between thefinger FG and the common electrode TL(2) and the electric fieldgenerated between the common electrode TL(2) and the detection electrodeRL(n) decreases. Accordingly, the amount of charge between the commonelectrode TL(2) and the detection electrode RL(n) decreases. As aresult, as shown in FIG. 2C, the amount of charge generated in responseto the supply of the drive signal Tx(2) decreases by ΔQ when the fingerFG touches compared with the case in which the finger FG does not touch.The difference in the amount of charge appears in the detection signalRx(n) as a difference of voltage, and is supplied to the unit amplifier13-n and then amplified.

In FIG. 2C, the horizontal axis represents the time and the verticalaxis represents the amount of charge. The amount of charge increases(increases upward in FIG. 2C) in response to a rise of the drive signalTx(2) and the amount of charge increases (increases downward in FIG. 2C)in response to a fall of the voltage of the drive signal Tx(2). At thistime, an increased amount of charge changes depending on the presence orabsence of the touch of the finger FG. Further, in this drawing, afterthe amount of charge increases upward, a reset of the amount of chargeis carried out before the amount of charge increases downward.Similarly, after the amount of charge increases downward, a reset of theamount of charge is carried out before the amount of charge increasesupward. In this manner, the amount of charge changes upward and downwardon the basis of the reset amount of charge.

By sequentially supplying the drive signals Tx(0) to Tx(p) to the commonelectrodes TL(0) to TL(p), the detection signals Rx(0) to Rx(p) havingthe voltage value depending on whether the finger FG touches a positionnear the respective intersection portions are output from each of theplurality of detection electrodes RL(0) to RL(p) intersecting with thecommon electrode to which the drive signal Tx(i) is supplied. Each ofthe detection signals Rx(0) to Rx(p) is sampled and converted into adigital signal by the use of an analog/digital conversion unit(hereinafter, referred to as an A/D conversion unit) at the time whenthe difference ΔQ arises in the amount of charge. By performing signalprocessing of the digital signal converted by the A/D conversion unit,coordinates of the touched position are extracted.

<Overall Configuration>

Next, an overall configuration of a liquid crystal display device 1 witha touch detection function (hereinafter, simply referred to also as aliquid crystal display device) will be described with reference toFIG. 1. FIG. 1 is a block diagram showing the configuration of theliquid crystal display device 1 with a touch detection function. Theliquid crystal display device 1 with a touch detection function includesa liquid crystal panel (display panel) 2, a display control device 5, asignal line selector 6, a touch control device 7 and a gate driver 8. InFIG. 1, the liquid crystal panel 2 is depicted schematically to make thedrawing easier to view and includes a liquid crystal panel unit (displaypanel unit) 3 and a touch detection panel unit 4. The configuration ofthe liquid crystal panel 2 will be described below with reference toFIG. 3 and FIG. 4.

The liquid crystal panel unit 3 and the touch detection panel unit 4share the drive electrodes. Scanning signals Vs0 to Vsp are supplied tothe liquid crystal panel unit 3 from the gate driver 8 and image signalsSLd(0) to SLd(p) are further supplied thereto from the display controldevice 5 via the signal line selector 6 to display images in accordancewith the image signals SLd(0) to SLd(p). The touch detection panel unit4 receives drive signals Tx(0) to Tx(p) supplied from the displaycontrol device 5 and outputs detection signals Rx(0) to Rx(p) to thetouch control device 7.

The display control device 5 has a control unit 9 and a drive circuit10, and the drive circuit 10 includes a signal line driver 11 that formsand outputs image signals and a drive electrode driver 12 that outputsthe drive signals Tx(0) to Tx(p). The control unit 9 receives a timingsignal and a control signal supplied to a control terminal Tt and animage signal supplied to an image terminal Td and supplies an imagesignal Sn in accordance with the image signal supplied to the imageterminal Td to the signal line driver 11. Though not particularlylimited, the signal line driver 11 temporally multiplexes the imagesignals Sn supplied from the control unit 9 and outputs the multiplexedsignal to the signal line selector 6. Namely, when one output terminalof the signal line driver 11 is viewed, two image signals are outputfrom one terminal while being temporally shifted.

Also, the control unit 9 supplies selection signals SEL1 and SEL2 todistribute temporally multiplexed image signals to mutually differentsignal lines in the signal line selector 6 to the signal line selector6. The signal line selector 6 distributes the image signals suppliedafter being multiplexed to mutually different signal lines based on theselection signals SEL1 and SEL2 and supplies the image signals as theimage signals SLd(0) to SLd(p) to the liquid crystal panel unit 3. Thesignal line selector 6 is disposed near the liquid crystal panel unit 3.By temporally multiplexing image signals as described above, the numberof wires to electrically connect the display control device 5 and theliquid crystal panel unit 3 can be reduced. In other words, the delay ofimage signals can be reduced by increasing the line width of the wireconnecting the display control device 5 and the liquid crystal panelunit 3.

The control unit 9 supplies a timing signal to the gate driver 8 basedon a timing signal and a control signal supplied to the control terminalTt. The gate driver 8 generates and supplies the scanning signals Vs0 toVsp to the liquid crystal panel unit 3 based on the supplied timingsignals. The scanning signals Vs0 to Vsp generated by the gate driver 8are, for example, pulse signals which become higher in levelsequentially from the scanning signal Vs0 to the scanning signal Vsp.

The drive electrode driver 12 in the drive circuit 10 receives selectionsignals TP(0) to TP(p) supplied from the touch control device 7 andsupplies the drive signals Tx(0) to Tx(p) to a plurality of the commonelectrodes TL(0) to TL(p) included in the liquid crystal panel 2. In thefirst embodiment, though not particularly limited, the drive signalsTx(0) to Tx(p) and the selection signals TP(0) to TP(p) correspond toeach other in a one-to-one manner. At the time of the touch detection,common electrodes that detect the touch (hereinafter, referred to asselected common electrodes) and common electrodes that do not detect thetouch (hereinafter, referred to as non-selected common electrodes) areselected from the plurality of common electrodes TL(0) to TL(p). Theselection is made by specifying the selected common electrodes based onthe selection signals TP(0) to TP(p).

For example, when the selection signal TP(i) specifies the commonelectrode TL(i) as the selected common electrode, the drive electrodedriver 12 outputs the drive signal Tx(i) corresponding to the selectionsignal TP(i) as a clock signal whose voltage changes periodically. Atthis time, for example, if the selection signal TP(n) specifies thecommon electrode TL(n) as a non-selected common electrode, the driveelectrode driver 12 fixes the drive signal Tx(n) corresponding to theselection signal TP(n) to a predetermined voltage. As described withreference to FIG. 2, whether or not the neighborhood of the commonelectrode is touched can be detected based on the periodical change ofthe voltage of the common electrode.

In the first embodiment, though not particularly limited, the touchcontrol device 7 forms the selection signals TP(0) to TP(p) inaccordance with selection information supplied to an external terminalTa. Thus, by specifying an arbitrary common electrode as a selectedcommon electrode in accordance with the selection information, whetheror not the neighborhood of a selected common electrode is touched can bedetected.

In the first embodiment, though not particularly limited, the touchcontrol device 7 sets a selection signal corresponding to a selectedcommon electrode to, for example, a high level in accordance with theselection information and sets a selection signal corresponding to anon-selected common electrode to a low level. Also, the touch controldevice 7 outputs a control signal (clock signal) TSVCOM whose voltagechanges periodically when detecting a touch. The drive electrode driver12 receives the selection signals TP(0) to TP(p) and the control signalTSVCOM and outputs the control signal TSVCOM as a drive signalcorresponding to a selection signal set to the high level. Also, thedrive electrode driver 12 outputs a ground voltage as a drive signalcorresponding to a selection signal set to the low level.

The liquid crystal display device 1 with a touch detection functionaccording to the first embodiment is of an in-cell type, and the driveelectrode TL(i) is used for both of the driving of touch detection andthe driving of liquid crystal. Namely, the drive electrode TL(i)functions to form an electric field for driving the liquid crystalbetween the drive electrode and a pixel electrode described below at thetime of the image display and functions to transmit a drive signal fortouch detection at the time of the touch detection. The image display bythe liquid crystal in the liquid crystal panel unit 3 and the touchdetection in the touch detection panel unit 4 are performed in atime-sharing manner so as to avoid temporal overlapping. Namely, thedisplay period in which an image is displayed and the touch detectionperiod in which the touch detection is performed are generated in atime-sharing manner so as not to be overlapped.

The drive electrode driver 12 supplies the drive signal Tx(i) to drivethe liquid crystal to the common electrode TL(i) in the liquid crystalpanel 2 in the display period in which the image display is performed,and supplies the drive signal Tx(i) for touch detection to the commonelectrode TL(i) in the liquid crystal panel 2 in the touch detectionperiod in which the touch detection is performed. Naturally, a driveelectrode driver for touch detection and a drive electrode driver fordriving liquid crystal may be separately provided in the drive circuit10. In addition, the control unit 9 outputs a touch-displaysynchronizing signal TSHD that distinguishes between the display periodand the touch detection period.

The touch control device 7 includes a detection signal processing unitTS that processes the detection signals Rx(0) to Rx(p) from the touchdetection panel unit 4, a drive signal forming unit 17 that forms theselection signals TP(0) to TP(p) and control signals TSVCOM, VCOMSEL andxVCOMSEL supplied to the drive electrode driver 12, and a control unit18 that controls the detection signal processing unit TS and the drivesignal forming unit 17. Here, the detection signal processing unit TSdetects whether the touch detection panel unit 4 is touched, and if itis touched, the detection signal processing unit TS performs theprocessing to determine coordinates of the touched position. Also, thedrive signal forming unit 17 specifies and controls an area where atouch is detected in the touch detection panel unit 4.

The detection signal processing unit TS will be first described. Thedetection signal processing unit TS includes a touch detection signalamplification unit 13 that receives the detection signals Rx(0) to Rx(p)from the touch detection panel unit 4 and amplifies the receiveddetection signals Rx(0) to Rx(p) and an A/D conversion unit 14 thatconverts an analog detection signal amplified by the touch detectionsignal amplification unit 13 into a digital signal. Here, the touchdetection signal amplification unit 13 performs an amplificationoperation by removing high frequency components (noise components) fromthe received detection signals Rx(0) to Rx(p). Also, as described abovewith reference to FIG. 2, the detection signals Rx(0) to Rx(p) aregenerated in response to the drive signal Tx(i) supplied to the commonelectrode TL(i). Thus, in the first embodiment, the A/D conversion unit14 is controlled by the control unit 18 so as to sample an amplifiedsignal from the touch detection signal amplification unit 13 and convertit into a digital signal in synchronization with the drive signal Tx(i).

Further, the detection signal processing unit TS includes a signalprocessing unit 15 that receives the digital signal obtained by theconversion operation of the A/D conversion unit 14 and performs signalprocessing on the digital signal and a coordinate extraction unit 16that extracts coordinates of the touched position from the signalobtained by the processing of the signal processing unit 15. The signalprocessing performed by the signal processing unit 15 includes theprocessing to remove noise components of higher frequencies than thesampling frequency by the A/D conversion unit 14 and detect whether thetouch detection panel unit 4 is touched. Coordinates of the touchedposition extracted by the coordinate extraction unit 16 are output froman output terminal Tout as coordinate information.

The drive signal forming unit 17 forms the selection signals TP(0) toTP(p) and the control signals TSVCOM, VCOMSEL and xVCOMSEL based on acontrol signal from the control unit 18 and supplies these signals tothe drive electrode driver 12. The control unit 18 receives thetouch-display synchronizing signal TSHD output from the control unit 9of the display control device 5 and selection information via theexternal terminal Ta, and when the touch-display synchronizing signalTSHD indicates the touch detection period, the control unit 18 controlsthe drive signal forming unit 17 to form the selection signals TP(0) toTP(p) and the control signals TSVCOM, VCOMSEL and xVCOMSEL.

Namely, the control unit 18 controls the drive signal forming unit 17 sothat selection signals corresponding to common electrodes specified byselection information are at a high level and remaining selectionsignals are at a low level. Also, in the touch detection period, thecontrol unit 18 controls the drive signal forming unit 17 so that thedrive signal forming unit 17 outputs the control signal TSVCOM whosevoltage changes periodically and the control signal VCOMSEL that becomesa high level in the touch detection period. The control signal xVCOMSELis a control signal obtained by inverting the phase of the controlsignal VCOMSEL. Namely, the control signal xVCOMSEL becomes a low levelin the touch detection period. Also, the control unit 18 controls theA/D conversion unit 14, the signal processing unit 15 and the coordinateextraction unit 16 so that the detection signals Rx(0) to Rx(p) receivedby the touch detection signal amplification unit 13 are converted andtouched coordinates are extracted in the touch detection period.

<Module>

FIG. 3A is a plan view showing an overview of a module in which theliquid crystal display device 1 with a touch detection functionaccording to the first embodiment is mounted. FIG. 3B is a sectionalview of the line B-B′ in FIG. 3A.

The liquid crystal panel 2 includes signal lines SL(0) to SL(p)extending in a longitudinal direction in FIG. 3A and arranged inparallel in a lateral direction and a plurality of common electrodesTL(0) to TL(p) extending in the same direction as the extendingdirection of the signal lines SL(0) to SL(p). Namely, the commonelectrodes TL(0) to TL(p) also extend in the longitudinal direction inFIG. 3A and are arranged in parallel in the lateral direction. Note thatscanning lines to which the selection signals Vs0 to Vsp are suppliedand the detection electrodes RL(0) to RL(p) that transmit the detectionsignals Rx(0) to Rx(p) extend in the lateral direction and are arrangedin parallel in the longitudinal direction, but are omitted in FIG. 3A.

In FIG. 3A, 2-U denotes a short side (first side) of the liquid crystalpanel 2 and 2-D denotes a short side (second side) of the liquid crystalpanel 2 opposite to the short side 2-U. Further, 2-L denotes a long sideof the liquid crystal panel 2 and 2-R denotes a long side of the liquidcrystal panel 2 opposite to the long side 2-L. Here, each of the shortsides 2-U and 2-D is a side parallel to the scanning lines and thedetection electrodes RL(0) to RL(p) and each of the long sides 2-L and2-R is a side parallel to the signal lines SL(0) to SL(p) and the commonelectrodes TL(0) to TL(p).

The display control device 5 and the signal line selector 6 describedwith reference to FIG. 1 are arranged along the short side 2-D of theliquid crystal panel 2. Namely, the display control device 5 and thesignal line selector 6 extend in a direction perpendicular to the signallines SL(0) to SL(p) and the common electrode TL(0) to TL(p). As will bedescribed below with reference to FIG. 5, the signal line selector 6 isformed on the same substrate as the liquid crystal panel 2, the signallines SL(0) to SL(p) are connected to the signal line selector 6, and animage signal output from the display control device 5 is supplied to thesignal lines SL(0) to SL(p) of the liquid crystal panel 2 via the signalline selector 6. Here, signals supplied from the display control device5 to the signal line selector 6 are an image signal and a selectionsignal. Since the liquid crystal panel 2 performs a color display, theimage signals supplied from the display control device 5 to the signalline selector 6 are image signals of R (red), G (green) and B (blue)corresponding to three primary colors and are shown as R/G/B in FIG. 3A.Also, selection signals are shown as SEL1 and SEL2 in FIG. 3A. Thesignal line selector 6 and the signal line driver 11 are related to thesignal lines SL(0) to SL(p) and so can be regarded as a signal linecircuit, and the signal line circuit can be regarded as being arrangedalong the short side 2-D of the liquid crystal panel 2.

Each of the signal lines SL(0) to SL(p) is formed on one main surface ofa TFT substrate 300 serving as a glass substrate. In the module shown inFIG. 3, a plurality of signal lines (for example, signal lines SL(0)0and SL(0)1) correspond to one common electrode (for example, the commonelectrode TL(0)) and each of the signal lines SL(0)0 and SL(0)1 includesthree signal lines corresponding to the image signals R, G and B. FIG.3B shows signal lines SL(0)0(R), SL(0)0(G) and SL(0)0(B) correspondingto the image signals R, G and B included in the signal line SL(0)0 andsignal lines SL(1)0(R), SL(1)0(G) and SL(1)0(B) corresponding to theimage signals R, G and B included in the signal line SL(1).

Here, the notation of the signal lines used in this specification willbe described. When described with respect to the signal line SL(0)0(R)and the signal line SL(1)0(R), the number in ( ) indicates the number ofthe corresponding common electrode, the next number indicates the numberof the pixel in the corresponding common electrode, and the alphabet in( ) indicates the three primary colors (R, G, B) of the pixel. Namely,the signal line SL(0)0(R) indicates a signal line that corresponds tothe common electrode TL(0) and transmits an image signal correspondingto red of the three primary colors in the 0-th pixel. Similarly, thesignal line SL(1)0(R) indicates a signal line that corresponds to thecommon electrode TL(1) arranged next to the common electrode TL(0) andtransmits an image signal corresponding to red of the three primarycolors in the 0-th pixel. Therefore, SL(1)1(R) and SL(1)1(G) shown inFIG. 3B indicate signal lines that correspond to the common electrodeTL(1) and transmit image signals corresponding to red and green of thethree primary colors in the first pixel.

As shown in FIG. 3B, an insulating layer 301 is further formed on onemain surface of the signal lines SL(0)0(R), SL(0)0(G), SL(0)0(B) and thelike corresponding to the image signals R, G and B and on one mainsurface of the TFT substrate 300, and the common electrodes TL(0) toTL(p) are formed on the insulating layer 301. An auxiliary electrode SMis formed in each of these common electrodes TL(0) to TL(p) and theauxiliary electrode SM is electrically connected to the common electrodeto reduce electric resistance of the common electrode. An insulatinglayer 302 is formed on the top surface of the common electrodes TL(0) toTL(p) and the auxiliary electrode SM and a pixel electrode LDP is formedon the top surface of the insulating layer 302. In FIG. 3B, each of CR,CB and CG is a color filter and a liquid crystal layer 303 is sandwichedbetween the color filters CR (red), CG (green) and CB (blue) and theinsulating layer 302. Here, the pixel electrode LDP is provided at anintersection of a scanning line and a signal line, and the color filterCR, CG or CB corresponding to each of the pixel electrodes LDP isprovided above each pixel electrode LDP. A black matrix BM is providedbetween the respective color filters CR, CG and CB.

FIG. 4 is a schematic diagram showing a relationship between thedetection electrodes RL(0) to RL(p) and the common electrodes TL(0) toTL(p). As shown in FIG. 4A, a CF glass substrate 400 serving as a glasssubstrate is provided on the upper surface of the color filters CR, CGand CB and the detection electrodes RL(0) to RL(p) are formed on theupper surface of the CF glass substrate 400. Further, a polarizing plate401 is formed above the detection electrodes RL(0) to RL(p). Note that,since the case of being viewed from above is taken as an example asshown in FIG. 4A, the surface is mentioned as the upper surface, but itis needless to say that the upper surface may be a lower surface or aside surface when the direction of viewing changes. Further, anelectrode of a capacitive element formed between the detectionelectrodes RL(0) to RL(p) and the common electrodes TL(0) to TL(p) isdepicted by a broken line in FIG. 4A.

As shown in FIG. 3A and FIG. 4C, each of the signal lines SL(0) to SL(p)and the common electrodes TL(0) to TL(p) extends in a longitudinaldirection, that is, in a long side direction and is arranged in parallelin a lateral direction, that is, in a short side direction. Meanwhile,the detection electrodes RL(0) to RL(p) are provided on the CF glasssubstrate 400 and arranged so as to intersect with the common electrodesTL(0) to TL(p) as shown in FIG. 4B. Namely, in FIG. 4B, the detectionelectrodes RL(0) to RL(p) extend in the lateral direction (short side)and are arranged in parallel in the longitudinal direction (long side).The detection signals Rx(0) to Rx(p) from the respective detectionelectrodes RL(0) to RL(p) are supplied to the touch control device 7. Inthe first embodiment, though not particularly limited, as shown in FIG.4B, the detection signals Rx(0) to Rx(p) are alternately fetched.

When viewed in a plan view, the signal lines SL(0) to SL(p) and thecommon electrodes TL(0) to TL(p) can be regarded as extending inparallel as shown in FIG. 3A. “Parallel” means the state in whichelectrodes extend from one end to the other end without intersectingwith each other, and even when a part or whole of one line is providedin an inclined state with respect to the other line, the state isassumed to be “parallel” if these lines do not intersect between one endand the other end.

Also, when the arrangement of the common electrodes TL(0) to TL(p) isviewed based on the signal line selector 6 and the display controldevice 5 as a reference point, each of the common electrodes TL(0) toTL(p) can be regarded as extending in a direction away from the signalline selector 6 and the display control device 5 as a reference point.In this case, the signal lines SL(0) to SL(p) can also be regarded asextending in a direction away from the signal line selector 6 and thedisplay control device 5 as a reference point.

Note that the signal lines and the pixel electrodes LDP shown in FIG. 3Bare omitted in FIG. 4A.

<Overall Configuration of Module>

FIG. 5 is a schematic plan view showing an overall configuration of amodule according to an embodiment and shows the overall configuration ofa module 500 mounted with the liquid crystal display device 1 with atouch detection function. Though schematically, FIG. 5 is depicted inconformity to an actual arrangement.

FIG. 5 shows the overall configuration of modules according to thesecond and third embodiments described below in addition to thataccording to the first embodiment. Components according to the secondand third embodiments will be described in detail below and so will bebriefly described here.

In FIG. 5, a reference character 501 denotes an area of the TFTsubstrate 300 described with reference to FIG. 3 and a referencecharacter 502 denotes an area having the TFT substrate 300 and the CFglass substrate 400 described with reference to FIG. 4. In the module500, the TFT substrate 300 is integrated. Namely, the TFT substrate 300is common in the area 501 and the area 502, and the CF glass substrate400, the detection electrodes RL(0) to RL(p), the polarizing plate 401and the like are further formed on the upper surface of the TFTsubstrate 300 in the area 502 as shown in FIG. 4.

In FIG. 5, 500-U denotes a short side of the module 500 and 500-Ddenotes a short side of the module 500 opposite to the short side 500-U.Also, 500-L denotes a long side of the module 500 and 500-R denotes along side of the module opposite to the long side 500-L.

In the area 502, the gate driver 8 shown in FIG. 1 is mounted along thelong sides 500-L and 500-R of the module 500. Namely, the gate drivers 8are mounted between the two long sides 500-L and 500-R of the module 500and the two long sides 2-L and 2-R of the liquid crystal panel 2 in thestate of sandwiching the plurality of common electrodes TL(0) to TL(p)therebetween. In this case, the scanning lines described with referenceto FIG. 1 extend along the short sides 500-U and 500-D of the module andare arranged in parallel in the direction of the long sides 500-L and500-R, and are connected to the gate driver 8. Also, the signal lineselector 6 described above is mounted in the area 502. In the firstembodiment, the signal line selector 6 is arranged along the short side2-D of the liquid crystal panel 2.

Meanwhile, the display control device 5 is mounted in the area 501. Inthe first embodiment, the display control device 5 is made up of asemiconductor integrated circuit device (hereinafter, referred to alsoas a semiconductor device) and a plurality of electronic components. Theelectronic components include a field effect transistor (hereinafter,referred to as MOSFET). A plurality of MOSFETs are formed on the TFTsubstrate 300, and the plurality of MOSFETs are formed in an area of theTFT substrate 300 covered with the semiconductor device constituting thedisplay control device 5. A second circuit CGW2 constituted of theplurality of MOSFETs covered with the semiconductor device is differentin the respective embodiments as will be described in detail below. Theconfiguration of the second circuit CGW2 according to the firstembodiment will be described in detail below with reference to FIG. 7 toFIG. 9. The semiconductor device mounted so as to cover the secondcircuit CGW2 includes the control unit 9 shown in FIG. 1 and the signalline driver 11 (FIG. 1).

The semiconductor device mounted so as to cover the second circuit CGW2is shown as DDIC in FIG. 5. The semiconductor device DDIC includes thesignal line driver 11 (FIG. 1) that drives the signal lines SL(0) toSL(p) and so will be referred to as a semiconductor device for driverbelow. In the first embodiment, though not particularly limited, thenumber of the semiconductor devices for driver DDIC is one. The displaycontrol device 5 shown in FIG. 1 is made up of the one semiconductordevice for driver DDIC, the second circuit CGW2 constituted of theplurality of MOSFETs formed to be sandwiched between the semiconductordevice for driver DDIC and the TFT substrate 300, and a first circuitCGW1 described below. However, the semiconductor device for driver DDICmay include only the signal line driver 11 shown in FIG. 1 and anothersemiconductor device may include the control unit 9 shown in FIG. 1.

The output of the signal line driver 11 (FIG. 1) in the semiconductordevice for driver DDIC is supplied to the signal lines SL(0) to SL(p)via the signal line selector 6. The second circuit CGW2 receives theselection signals TP(0) to TP(p) and the control signals VCOMSEL andxVCOMSEL from the touch control device 7 and outputs the selectionsignals TP(0) to TP(p) in the touch detection period. The selectionsignals TP(0) to TP(p) output from the second circuit CGW2 are suppliedto the first circuit CGW1 via control lines SS(0) to SS(p) correspondingto the common electrodes TL(0) to TL(p) in a one-to-one manner. Thecontrol lines SS(0) to SS(p) are arranged in the liquid crystal panel 2.

In the first embodiment, at least some of the plurality of signal linesSL(0) to SL(p) are used as the control lines SS(0) to SS(p) in the touchdetection period. Namely, at least some signal lines of the plurality ofsignal lines constituting the respective signal lines SL(0) to SL(p) areused also as the control lines SS(0) to SS(p). Thus, the output of thesecond circuit CGW2 is transmitted to some of the signal lines via thesignal line selector 6 and supplied to the first circuit CGW1 in thetouch detection period.

Though omitted in FIG. 5, the semiconductor device for driver DDICsupplies a timing signal to the gate driver 8. The gate driver 8 formsthe scanning signals Vs0 to Vsp in accordance with the supplied timingsignal and supplies the signals to the scanning lines (not shown).

The detection electrodes RL(0) to RL(p) described with reference to FIG.4 are connected to a flexible cable FB1 via a wire arranged between thelong sides 500-L and 500-R of the module 500 and the long sides 2-L and2-R of the display panel 2. The touch control device 7 described withreference to FIG. 1 is mounted to the flexible cable FB1 and thedetection signals Rx(0) to Rx(p) in the detection electrodes RL(0) toRL(p) are supplied to the touch control device 7 via wires in theflexible cable FB1. Also, a flexible cable FB2 is connected to the area501 and terminals of the semiconductor device for driver DDIC and thesecond circuit CGW2 are connected to wires in the flexible cable FB2.

Further, a connector CN is mounted to the flexible cable FB2. Theflexible cables FB1 and FB2 are electrically connected via the connectorCN. A plurality of signals are transmitted/received between thesemiconductor device for driver DDIC and second circuit CGW2 and thetouch control device 7 via the connector CN. In the first embodiment,though not particularly limited, the touch control device 7 is made upof one semiconductor device. To distinguish from the semiconductordevice for driver, the semiconductor device constituting the touchcontrol device 7 is referred to as the semiconductor device for touch 7.

In FIG. 5, among the plurality of signals transmitted/received betweenthe semiconductor device for driver DDIC and second circuit CGW2 and thesemiconductor device for touch 7, only the touch-display synchronizingsignal TSHD and the control signals TSVCOM, VCOMSEL and xVCOMSEL areshown. As described with reference to FIG. 1, the touch-displaysynchronizing signal TSHD is a control signal that distinguishes betweenthe display period and the touch detection period. The control signalTSVCOM is, as described above, a clock signal whose voltage changesperiodically in the touch detection period. The control signal TSVCOMserving as a clock signal is supplied to the selected common electrodeTL(i) selected to detect a touch as the drive signal Tx(i) in the touchdetection period. Thus, the control signal TSVCOM can be regarded as acommon drive signal.

In the first embodiment, the control signal (common drive signal) TSVCOMand the control signals VCOMSEL and xVCOMSEL are supplied from thesemiconductor device for touch 7 to a signal wire 503 via the connectorCN. The signal wire 503 is arranged so as to surround the liquid crystalpanel 2. Namely, the signal wire 503 is arranged in an area between thelong sides 500-L and 500-R of the module 500 and the long sides 2-L and2-R of the liquid crystal panel 2 and in an area between the short sides500-U and 500-D of the module 500 and the short sides 2-U and 2-D of theliquid crystal panel 2. The signal wire 503 is connected to the firstcircuit CGW1 and the control signal (common drive signal) TSVCOM and thecontrol signals VCOMSEL and xVCOMSEL are supplied from the semiconductordevice for touch 7 to the first circuit CGW1 via the signal wire 503.

In the module 500 shown in FIG. 5, the first circuit CGW1 and the secondcircuit CGW2 are arranged along the two short sides 2-U and 2-D of thedisplay panel 2. Namely, the module 500 includes the first circuit CGW1arranged along the one short side 2-U of the display panel 2 and thesecond circuit CGW2 arranged along the other short side 2-D of thedisplay panel 2. In FIG. 5, the second circuit CGW2 arranged along theother short side 2-D of the display panel 2 is covered with thesemiconductor device for driver DDIC. Also, the first circuit CGW1arranged along the one short side 2-U of the display panel 2 is formedbetween the short side 2-U of the display panel 2 and the short side500-U of the module 500. Though not particularly limited, the firstcircuit CGW1 is also constituted of the MOSFET formed on the TFTsubstrate 300.

In the first embodiment, the second circuit CGW2 supplies the selectionsignals TP(0) to TP(p) to the first circuit CGW1 via the control linesSS(0) to SS(p) arranged in the liquid crystal panel 2 in the touchdetection period. The first circuit CGW1 supplies the control signalTSVCOM to a selected common electrode and supplies a predeterminedvoltage to a non-selected common electrode in accordance with thesupplied selection signals TP(0) to TP(p). Namely, in the touchdetection period, the drive signals Tx(0) to Tx(p) are supplied from thefirst circuit CGW1 to the common electrodes TL(0) to TL(p). Therefore,in the first embodiment, the first circuit CGW1 can be regarded as adrive electrode circuit (first drive electrode circuit).

The second circuit CGW2 only needs to transmit the selection signalsTP(0) to TP(p) to the control line SS(0) to SS(p) in the touch detectionperiod and so may have a low driving ability. Thus, the area where thesecond circuit CGW2 is formed can be made smaller.

The size of an edge frame (upper and lower frame) of the liquid crystaldisplay device 1 with a touch detection function depends on the size ofan area between the short side 500-D of the module 500 and the shortside 2-D of the display panel 2. For the reduction in width of the edgeframe, a short side DDL of the semiconductor device for driver DDIC ismade shorter. In the first embodiment, the area occupied by the secondcircuit CGW2 can be made smaller and thus the reduction in width of theedge frame can be achieved while maintaining a state in which the secondcircuit CGW2 is covered with the semiconductor device for driver DDIC.

Further, in the first embodiment, instead of arranging signal wires thattransmit the selection signals TP(0) to TP(p) in the area between thelong sides 500-L and 500-R of the module 500 and the long sides 2-L and2-R of the liquid crystal panel 2, the control lines arranged in theliquid crystal panel 2 are used. Thus, it is possible to suppress theincrease of the edge frame (transverse edge frame) that depends on thesize of the area between the long sides 500-L and 500-R of the module500 and the long sides 2-L and 2-R of the liquid crystal panel 2.

Accordingly, the liquid crystal display device 1 capable of achievingthe reduction in width of the edge frame can be provided.

Further, in the first embodiment, at least some of the signal linesSL(0) to SL(p) are used as the control lines SS(0) to SS(p) in the touchdetection period and thus there is no need to provide a new wire in theliquid crystal panel 2. Accordingly, it is possible to suppress the costincrease.

Though not particularly limited, the semiconductor device for driverDDIC is formed as Chip On Glass (COG). Also, each of the signal lineselector 6 and the gate driver 8 may be constituted of a semiconductordevice. Also in such a case, the semiconductor device may be formed asCOG. In FIG. 5, R, G and B shown on four sides of the liquid crystalpanel 2 indicate sub-pixels constituting one pixel.

<Liquid Crystal Element Array>

Next, the circuit configuration of the liquid crystal panel 2 will bedescribed. FIG. 6 is a circuit diagram showing a circuit configurationof the liquid crystal panel 2. In FIG. 6, each of a plurality ofreference characters SPix indicated by a one-dot chain line denotes oneliquid crystal display element (pixel). The liquid crystal displayelements (pixels) SPix are arranged in a matrix form in the liquidcrystal panel 2 to constitute a liquid crystal element array (pixelarray) LCD. The liquid crystal element array (pixel array) LCD includesthe plurality of scanning lines GL(0) to GL(p) arranged in each row andextending in the row direction and the signal lines SL(0)0(R), SL(0)0(G)and SL(0)0(B) to SL(p)p(R), SL(p)p(G) and SL(p)p(B) arranged in eachcolumn and extending in the column direction. The liquid crystal elementarray LCD further includes the common electrodes TL(0) to TL(p) arrangedin each column and extending in the column direction. FIG. 6 shows apart of the liquid crystal element array (pixel array) relating to thescanning lines GL(0) to GL(2), the signal lines SL(0)0(R), SL(0)0(G) andSL(0)0(B) to SL(1)0(R), SL(1)0(G) and SL(1)0(B), and the commonelectrodes TL(0) and TL(1).

In FIG. 6, to make the description easier, the common electrodes TL(0)and TL(1) are depicted as if they are arranged in respective columns,but it should be understood that one common electrode is arranged for aplurality of signal lines as described with reference to FIG. 3A andFIG. 3B. Naturally, the common electrodes may be arranged in respectivecolumns of the liquid crystal element array LCD as shown in FIG. 6. Inany case, each of the common electrodes TL(0) to TL(p) is arranged in acolumn of the liquid crystal element array LCD so as to be parallel tothe signal lines.

Each liquid crystal display element (pixel) SPix arranged at anintersection of a row and a column of the liquid crystal element arrayLCD includes a thin film transistor Tr formed on the TFT glass substrate300 and a liquid crystal element LC whose one terminal is connected tothe source of the thin film transistor Tr. In the liquid crystal elementarray LCD, gates of the thin film transistors Tr of the plurality ofliquid crystal display elements SPix arranged in the same row areconnected to the scanning line arranged in the same row, and drains ofthe thin film transistors Tr of the plurality of liquid crystal displayelements SPix arranged in the same column are connected to the signalline arranged in the same column. In other words, the plurality ofliquid crystal display elements SPix are arranged in a matrix form, ascanning line is arranged in each row, and the plurality of liquidcrystal display elements SPix arranged in the corresponding row areconnected to the scanning line. Also, a signal line is arranged in eachcolumn and the liquid crystal display elements SPix arranged in thecorresponding column are connected to the signal line. Further, theother ends of the liquid crystal elements LC of the plurality of liquidcrystal display elements SPix arranged in the same column are connectedto the common electrode arranged in the column.

When described with respect to the example shown in FIG. 6, the gate ofthe thin film transistor Tr of each of the plurality of liquid crystaldisplay elements SPix arranged in the uppermost row in FIG. 6 isconnected to the scanning line GL(0) arranged in the uppermost row.Further, the drain of the thin film transistor Tr of each of theplurality of liquid crystal display elements SPix arranged in theleftmost column in FIG. 6 is connected to the signal line SL(0)0(R)arranged in the leftmost column. Also, the other end of the liquidcrystal element of each of the plurality of liquid crystal displayelements SPix arranged in the leftmost column is connected to the commonelectrode TL(0) arranged in the leftmost column in FIG. 6. As alreadydescribed above, one common electrode corresponds to a plurality ofsignal lines. Thus, in the example shown in FIG. 6, the common electrodeTL(0) can be regarded as a common electrode shared by three columns.

One liquid crystal display element SPix corresponds to one sub-pixeldescribed above. Thus, sub-pixels of three primary colors of R, G and Bare formed of three liquid crystal display elements SPix. In FIG. 6, onepixel Pix is formed of three liquid crystal display elements SPixarranged consecutively in the same row and colors are expressed by thepixel Pix. Namely, in FIG. 6, the liquid crystal display element SPixshown as 600R serves as a sub-pixel SPix(R) of R (red), the liquidcrystal display element SPix shown as 600G serves as a sub-pixel SPix(G)of G (green), and the liquid crystal display element SPix shown as 600Bserves as a sub-pixel SPix(B) of B (blue). Thus, the sub-pixel SPix(R)shown as 600R is provided with a red color filter CR as a color filter,the sub-pixel SPix(G) shown as 600G is provided with a green colorfilter CG as a color filter, and the sub-pixel SPix(B) shown as 600B isprovided with a blue color filter CB as a color filter.

Among the signals representing one pixel, an image signal correspondingto R is supplied to the signal line SL(0)0(R) from the signal lineselector 6, an image signal corresponding to G is supplied to the signalline SL(0)0(G) from the signal line selector 6, and an image signalcorresponding to B is supplied to the signal line SL(0)0(B) from thesignal line selector 6.

Though not particularly limited, the thin film transistor Tr in eachliquid crystal display element SPix is an N-channel MOSFET. The scanningsignals Vs0 to Vsp (FIG. 1) in a pulse shape which become higher inlevel sequentially in this order are supplied to the scanning linesGL(0) to GL(p) from the gate driver 8. Namely, in the liquid crystalelement array LCD, the voltage of scanning lines becomes higher in levelsequentially from the scanning line GL(0) arranged in the upper rowtoward the scanning line GL(p) arranged in the lower row. Accordingly,in the liquid crystal element array LCD, the thin film transistors Tr inthe liquid crystal display elements SPix are sequentially brought intoconduction from the liquid crystal display element SPix arranged in theupper row toward the liquid crystal display element SPix arranged in thelower row.

When the thin film transistor Tr is brought into conduction, the pixelsignal being supplied to the signal line at that time is supplied to theliquid crystal element LC via the thin film transistor in conduction.The electric field of the liquid crystal element LC changes inaccordance with the value of the pixel signal supplied to the liquidcrystal element LC, and the modulation of light passing through theliquid crystal element LC changes. Accordingly, a color image inaccordance with the image signal supplied to the signal lines SL(0)0(R),SL(0)0(G) and SL(0)0(B) to SL(p)p(R), SL(p)p(G) and SL(p)p(B) isdisplayed on the liquid crystal panel 2 in synchronization with thescanning signals Vs0 to Vsp supplied to the scanning lines GL(0) toGL(p).

Here, the correspondence between the arrangement of the module 500 shownin FIG. 5 and the circuit diagram shown in FIG. 6 will be describedbelow.

The liquid crystal element array (pixel array) LCD has a pair of sidessubstantially parallel to the row of the array and a pair of sidessubstantially parallel to the column of the array. The pair of sidesparallel to the row of the liquid crystal element array LCD correspondsto the short sides 2-U (first side) and 2-D (second side) of the liquidcrystal panel 2 shown in FIG. 5 and the pair of sides parallel to thecolumn of the liquid crystal element array LCD corresponds to the longsides 2-L and 2-R of the liquid crystal panel 2.

In the liquid crystal element array LCD, as shown in FIGS. 3A, 4C and 5,the signal line selector 6, the semiconductor device for driver DDIC andthe second circuit CGW2 are arranged along one side of the pair of sidesparallel to the row, that is, one short side 2-D (second side) of theliquid crystal panel. In the liquid crystal element array LCD, the imagesignal from the signal line driver 11 in the semiconductor device fordriver DDIC is supplied to the signal lines SL(0)0(R), SL(0)0(G) andSL(0)0(B) to SL(p)p(R), SL(p)p(G) and SL(p)p(B) via the signal lineselector 6 on this one side (short side 2-D of the liquid crystal panel2). Also, the selection signals TP(0) to TP(p) from the second circuitCGW2 arranged along the one side (short side 501-D of the liquid crystalpanel 2) are supplied to the first circuit (first drive electrodecircuit) CGW1 via the signal lines SL(0) to SL(p). The first circuit(first drive electrode circuit) CGW1 is arranged along the other side(short side 2-U (first side) of the liquid crystal panel 2) parallel tothe row of the liquid crystal element array (pixel array) LCD andsupplied to one ends of the common electrodes TL(0) to TL(p).

In the liquid crystal element array LCD, the gate drivers 8 are arrangedalong a pair of sides parallel to the column, that is, a pair of thelong sides 2-L and 2-R of the liquid crystal panel 2. In the liquidcrystal element array (pixel array) LCD, the scanning signals Vs0 to Vspfrom the gate driver 8 are supplied to the scanning lines GL(0) to GL(p)on the pair of sides (2-L and 2-R).

Since the liquid crystal display device 1 according to the firstembodiment is of an in-cell type, the common electrode TL is oneelectrode of the liquid crystal display element SPix, and apredetermined voltage is supplied thereto in the display period and adrive signal is supplied thereto from the first circuit (first driveelectrode circuit) CGW1 in the touch detection period. If the drain ofthe thin film transistor Tr is viewed as the other electrode of theliquid crystal display element SPix, the other electrode of the liquidcrystal display element SPix is a signal line in the display period andan image signal is supplied thereto. Further, in the first embodiment,some signal lines of the signal lines SL(0) to SL(p) are used as thecontrol lines SS(0) to SS(p) to transmit the selection signals TP(0) toTP(p) from the second circuit CGW2 to the first circuit (first driveelectrode circuit) CGW1 in the touch detection period.

The case in which the number of sub-pixels constituting one pixel isthree has been described, but the present embodiment is not limited tothis. For example, one pixel may be formed from sub-pixels including oneor more colors of white (W), yellow (Y) and complementary colors of RGB(cyan (C), magenta (M) and yellow (Y)) in addition to RGB describedabove.

<Configuration of Liquid Crystal Display Device 1>

FIG. 7 is a block diagram showing the configuration of the liquidcrystal display device 1 according to the first embodiment. FIG. 7 showsthe common electrodes, the first circuit CGW1, the second circuit CGW2and the semiconductor device for driver DDIC of the module 500 shown inFIG. 5 in detail. Though schematically, FIG. 7 is depicted in conformityto an actual arrangement.

In FIG. 7, TL(0) to TL(p) denote common electrodes and the commonelectrodes TL(0), TL(1) and TL(p) are shown as representative examples.Further, in FIG. 7, broken lines depicted on the common electrodesTL(0), TL(1) and TL(p) indicate signal lines and one-dot chain linesindicate the scanning lines GL(0) to GL(p).

In FIG. 7, each of SP11 to SP16 denotes a terminal formed on the TFTsubstrate 300 and the terminals SP11 to SP16 constitute a terminal group(SP11 to SP16) corresponding to one common electrode. Since the threecommon electrodes TL(0), TL(1) and TL(p) are shown in FIG. 7, three setsof terminal groups (SP11 to SP16) are shown. The terminals SP11 to SP16are connected to terminals indicated by circle marks ∘ of thesemiconductor device for driver DDIC and image signals are supplied fromthe terminals (∘ marks) of the semiconductor device for driver DDIC inthe display period. In the touch detection period, the semiconductordevice for driver DDIC puts the terminals of circle marks o into ahigh-impedance state.

The signal line selector 6 (FIG. 1) is constituted of a plurality ofunit signal line selectors 6(0) to 6(p). Each of the unit signal lineselectors 6(0) to 6(p) has the same configuration and each unit signalline selector connects the terminals SP11 to SP16 to signal linesarranged on the common electrodes corresponding to the terminals SP11 toSP16 in accordance with the voltages of the selection signals SEL1 andSEL2. In FIG. 7, when described with respect to the unit signal lineselector 6(0) depicted on the leftmost side, the unit signal lineselector 6(0) connects the terminal SP11 to the signal line SL(0)0(R) orSL(0)0(B) in accordance with the voltages of the selection signals SEL1and SEL2. For example, if the voltage of the selection signal SEL1 orSEL2 is at a high level, the unit signal line selector 6(0) connects theterminal SP11 to the signal line SL(0)0(R) or SL(0)0(B).

Accordingly, by selectively setting the selection signals SEL1 and SEL2to the high level in the display period, an image signal supplied fromthe semiconductor device for driver DDIC to the terminal SP11 can besupplied to the signal line SL(0)0(R) or SL(0)0(B). The same is true ofthe remaining terminals SP12 to SP16. In the display period, thesemiconductor device for driver DDIC supplies an image signal to each ofthe terminals SP11 to SP16 in a time-sharing manner and selectively setsthe voltage of the selection signals SEL1 and SEL2 to the high level,thereby supplying the image signal to an appropriate signal line.

Meanwhile, in the touch detection period, the semiconductor device fordriver DDIC sets each of the selection signals SEL1 and SEL2 to the highlevel. Accordingly, the unit signal line selector 6(0) connects theterminal SP11 to the signal lines SL(0)0(R) and SL(0)0(B). For each ofthe remaining terminals SP12 to SP16, the unit signal line selector 6(0)similarly connects two signal lines to one terminal.

The unit signal line selector 6(0) has been taken as an example in thedescription above, but the same is true of the remaining unit signalline selectors 6(1) to 6(p).

In the first embodiment, the second circuit CGW2 is made up of aplurality of unit selection circuits UCG2(0) to UCG2(p) and the firstcircuit (first drive electrode circuit) CGW1 is made up of a pluralityof unit drive electrode circuits UCG1(0) to UCG1(p). Each of theplurality of unit selection circuits UCG2(0) to UCG2(p) has the sameconfiguration and each of the plurality of unit drive electrode circuitsUCG1(0) to UCG1(p) also has the same configuration. Each of the unitselection circuits UCG2(0) to UCG2(p) and the unit drive electrodecircuits UCG1(0) to UCG1(p) corresponds to the common electrodes TL(0)to TL(p) in a one-to-one manner. When described with respect to the unitselection circuits UCG2(0), UCG2(1) and UCG2(p) and the unit driveelectrode circuits UCG1(0), UCG1(1) and UCG1(p) shown in FIG. 7, theunit selection circuit UCG2(0) and the unit drive electrode circuitUCG1(0) correspond to the common electrode TL(0). Similarly, the unitselection circuit UCG2(1) and the unit drive electrode circuit UCG1(1)correspond to the common electrode TL(1) and the unit selection circuitUCG2(p) and the unit drive electrode circuit UCG1(p) correspond to thecommon electrode TL(p).

Next, the unit selection circuit UCG2(0) and the corresponding unitdrive electrode circuit UCG1(0) are taken as an example to describe therelationship to the corresponding common electrode TL(0). The unitselection circuit UCG2(0) includes the switch circuit SW2. The controlsignals VCOMSEL and xVCOMSEL and the selection signal TP(0)corresponding to the common electrode TL(0) are supplied to the switchcircuit SW2. The switch circuit SW2 is brought into conduction (ONstate) by the control signals VCOMSEL and xVCOMSEL in the touchdetection period and transmits the selection signal TP(0) to theterminal SP16. Accordingly, the selection signal TP(0) is transmitted tothe control line SS(0). In the first embodiment, the control line SS(0)is the signal line SL(0)2(B), and an image signal representing blue (B)is supplied thereto from the semiconductor device for driver DDIC viathe unit signal line selector 6(0) in the display period. In FIG. 7, thesignal line SL(0)2(B) is denoted as SS(0)[SL(0)2(B)] in order toindicate that it is used also as the control line SS(0) in atime-sharing manner.

The unit drive electrode circuit UCG1(0) corresponding to the commonelectrode TL(0) includes the switch circuit SW1 and a unit driveelectrode driver 12(0). The switch circuit SW1 is connected between thecontrol line SS(0) and the unit drive electrode driver 12(0) and iscontrolled by the control signal VCOMSEL. The switch circuit SW1electrically connects the control line SS(0) and the unit driveelectrode driver 12(0) in the touch detection period and electricallyseparates the control line SS(0)[SL(0)2(B)] in the display period. Inother words, the switch circuit SW1 is a separation circuit thatelectrically separates the control line SS(0)[SL(0)2(B)] and the unitdrive electrode driver 12(0) in the display period.

In the first embodiment, an image signal from the semiconductor devicefor driver DDIC is supplied to the terminals SP11 to SP16 and thensupplied to the signal line SL(0) via the unit signal line selector 6(0)in the display period. In the example of FIG. 7, the image signal issupplied to the signal lines SL(0)0(R), SL(0)0(B), SL(0)2(R) andSL(2)2(B) and an image is displayed in accordance with the image signal.

Meanwhile, in the touch detection period, the semiconductor device fordriver DDIC puts the output terminal (o mark) thereof into ahigh-impedance state. At this time, the switch circuit SW2 constitutingthe unit selection circuit UCG2(0) is brought into conduction by thecontrol signals VCOMSEL and xVCOMSEL, and the selection signal TP(0)output from the semiconductor device for touch 7 is transmitted to thecontrol line SS(0)[SL(0)2(B)] via the switch circuit SW2 and thensupplied to the unit drive electrode circuit UCG1(0) via the controlline SS(0). In the unit drive electrode circuit UCG1(0), the switchcircuit SW1 is brought into conduction by the control signal VCOMSEL inthe touch detection period and supplies the supplied selection signalTP(0) to the unit drive electrode driver 12(0). The unit drive electrodedriver 12(0) connects the drive electrode TL(0) to the signal wire 503or a voltage wire 700 depending on whether or not the supplied selectionsignal TP(0) specifies the common electrode as a selected commonelectrode. Here, the control signal TSVCOM as a common drive signal issupplied to the signal wire 503 and a voltage VCOMDC corresponding tothe ground voltage is supplied to the voltage wire 700.

When the selection signal TP(0) specifies the corresponding commonelectrode TL(0) as a selected common electrode, the unit drive electrodedriver 12(0) connects the signal wire 503 to the common electrode TL(0).Meanwhile, when the selection signal TP(0) specifies the correspondingcommon electrode TL(0) as a non-selected common electrode, the unitdrive electrode driver 12(0) connects the voltage wire 700 to the commonelectrode TL(0). Accordingly, when the common electrode TL(0) isspecified as a selected common electrode in the touch detection period,the control signal TSVCOM whose voltage changes periodically is suppliedas the drive signal Tx(0). As a result, whether or not the neighborhoodof the common electrode TL(0) is touched can be detected. Meanwhile,when the common electrode TL(0) is specified as a non-selected commonelectrode in the touch detection period, the voltage VCOMDC as a groundvoltage is supplied to the common electrode TL(0).

The switch circuit SW2 constituting the unit selection circuit UCG2(0)is put into a high-impedance state in the display period. Further, inthe display period, the switch circuit SW1 operates as a separationcircuit. Accordingly, an image signal supplied to the terminal SP16 canbe transmitted to the signal line SL(0)2(B) and the image signal can besupplied to a pixel connected to the signal line SL(0)2(B).

The other unit selection circuits UCG2(1) to UCG2(p) and unit driveelectrode circuits UCG1(1) to UCG(p) operate in the same manner as theabove-described unit selection circuit UCG2(0) and unit drive electrodecircuit UCG1(0). In the example of FIG. 7, among the signal linescorresponding to the common electrode TL(1), the signal line SL(1)2(B)is used as the control line SS(1) in the touch detection period. Also,among the signal lines corresponding to the common electrode TL(p), thesignal line SL(p)2(B) is used as the control line SS(p) in the touchdetection period.

In the first embodiment, the drive electrode driver 12 shown in FIG. 1can be regarded as being constituted of the unit drive electrode drivers12(0) to 12(p).

<Configuration of Unit Selection Circuit and Unit Drive ElectrodeCircuit>

Next, the configuration of the unit selection circuits UCG2(0) toUCG2(p) and the unit drive electrode circuits UCG1(0) to UCG1(p) shownin FIG. 7 will be described. Here, the unit selection circuit UCG2(0)and the unit drive electrode circuit UCG1(0) will be described as anrepresentative example.

FIG. 8 is a circuit diagram showing principal parts in the configurationof the liquid crystal display device 1 according to the firstembodiment. FIG. 8 shows the configuration of the unit selection circuitUCG2(0) and the unit drive electrode circuit UCG1(0), the commonelectrode TL(0) and pixels for two rows. In in order to prevent thedrawing from being complicated, only the terminals SP11 to SP13 and SP16of the terminals SP11 to SP16 are shown in FIG. 8. Also, among aplurality of signal lines, only the signal lines SL(0)0(R), SL(0)0(G)and SL(0)0(B) and the signal line SL(0)2(B) are shown. Here, since thesignal line SL(0)2(B) functions as the control line SS(0) in the touchdetection period, it is denoted as SS(0)[SL(0)2(B)]. Note that R, G andB in FIG. 8 represent pixels.

Further, FIG. 8 shows a state of the unit signal line selector 6(0) inthe touch detection period. Namely, the state in which the unit signalline selector 6(0) connects each of the terminals SP11 to SP13 and SP16and the signal line SL(0) based on the selection signals SEL1 and SEL2is shown.

The unit signal line selector 6(0) includes a plurality of switches S11whose ON/OFF is controlled by the selection signal SEL1 and a pluralityof switches S12 whose ON/OFF is controlled by the selection signal SEL2.In the display period, the selection signals SEL1 and SEL2 arecomplementarily set to the high level, so that the switch S11 and theswitch S12 are complementarily turned on. Accordingly, an image signalsupplied to each of the terminals SP11 to SP16 is supplied to anappropriate signal line. Meanwhile, in the touch detection period,though not particularly limited, both of the selection signals SEL1 andSEL2 are set to the high level. Accordingly, as shown in FIG. 8, theterminals SP11 to SP16 are connected to a plurality of signal linescorresponding to the common electrode TL(0).

The switch circuit SW2 constituting the unit selection circuit UCG2(0)includes a P-channel type MOSFET (hereinafter, referred to as P-typeMOSFET) TP1 and an N-channel type MOSFET (hereinafter, referred to asN-type MOSFET) TN1. One electrode (source or drain) of the P-type MOSFETTP1 is connected to the terminal SP16 via a node n1 and one electrode(drain or source) of the N-type MOSFET TN1 is also connected to theterminal SP16 via the node n1. The other electrode (drain or source) ofthe P-type MOSFET TP1 and the other electrode (source or drain) of theN-type MOSFET TN1 are connected to a node n2 in common and the selectionsignal TP(0) from the semiconductor device for touch 7 is supplied tothe node n2. The control signal xVCOMSEL is supplied to the gate of theP-type MOSFET TP1 and the control signal VCOMSEL is supplied to the gateof the N-type MOSFET TN1.

The semiconductor device for touch 7 sets the control signal VCOMSEL tothe high level and sets the control signal xVCOMSEL to the low level inthe touch detection period. Also, the semiconductor device for touch 7sets the selection signal corresponding to the common electrode to bespecified as a selected common electrode to the high level and sets theselection signal corresponding to the common electrode to be specifiedas a non-selected common electrode to the low level. For example, whenthe common electrode TL(0) is specified as a selected common electrode,the semiconductor device for touch 7 sets the selection signal TP(0)corresponding to the common electrode TL(0) to the high level, and whenthe common electrode TL(0) is specified as a non-selected commonelectrode, the semiconductor device for touch 7 sets the selectionsignal TP(0) to the low level.

Accordingly, each of the P-type MOSFET TP1 and the N-type MOSFET TN1constituting the switch circuit SW2 is turned on in the touch detectionperiod and supplies the selection signal TP(0) supplied to the node n2to the terminal SP16 via the node n1. Meanwhile, in the display period,the control signal VCOMSEL is set to the low level and the controlsignal xVCOMSEL is set to the high level. Accordingly, each of theP-type MOSFET TP1 and the N-type MOSFET TN1 is turned off. As a result,the node n1 serving as an output terminal of the switch circuit SW2 isput into a high-impedance state.

In the touch detection period, the selection signal TP(0) supplied tothe terminal SP16 propagates through the control line SS(0) and issupplied to the unit drive electrode circuit UCG1(0). Namely, theselection signal TP(0) is supplied to the switch circuit SW1 in the unitdrive electrode circuit UCG1(0). The switch circuit SW1 includes aswitch S40 connected between the control line SS(0) and a signal wire800. The switch S40 is controlled by the control signal VCOMSEL. Sincethe control signal VCOMSEL is set to the high level in the touchdetection period as described above, the switch circuit SW1 is turned onin the touch detection period and turned off in the display period.

The unit drive electrode driver 12(0) constituting the unit driveelectrode circuit UCG1(0) includes a P-type MOSFET TP2, a buffer circuitBF1, an inverter circuit IV1, switches S20 to S23 and switches S30 toS33. Each of the switches S20 to S23 is connected in parallel betweenthe voltage wire 700 and the common electrode TL(0) and each of theswitches S30 to S33 is connected in parallel between the signal wire 503and the common electrode TL(0). ON/OFF of each of the switches S20 toS23 is controlled by an output signal of the inverter circuit IV1 andON/OFF of each of the switches S30 to S33 is controlled by an outputsignal of the buffer circuit BF1. The input of the inverter circuit IV1and the input of the buffer circuit BF1 are connected to the signal wire800. The signal wire 800 is connected to the drain of the P-type MOSFETTP2. The source of the P-type MOSFET TP2 is connected to a voltage VGLcorresponding to the ground voltage, and the control signal VCOMSEL issupplied to the gate thereof.

The control signal VCOMSEL is set to the high level in the touchdetection period and thus the P-type MOSFET TP2 is turned off.Accordingly, the voltage of the signal wire 800 becomes the same voltageas that of the selection signal TP(0) supplied via the switch circuitSW1. When the common electrode TL(0) is specified as a selected commonelectrode, the selection signal TP(0) is set to the high level, so thatthe buffer circuit BF1 outputs a high level and the inverter circuit IV1outputs a low level. Accordingly, each of the switches S30 to S33 isturned on and the common electrode TL(0) is connected to the signal wire503 via the switches S30 to S33. The control signal TSVCOM supplied tothe signal wire 503 is a clock signal whose voltage changes periodicallyin the touch detection period. Thus, when the common electrode TL(0) isspecified as a selected common electrode, a drive signal whose voltagechanges periodically is supplied, and whether or not the neighborhood ofthe common electrode TL(0) is touched can be detected.

Meanwhile, when the common electrode TL(0) is specified as anon-selected common electrode, the selection signal TP(0) is set to thelow level. The low level of the selection signal TP(0) is transmittedthrough the signal wire 800 and is supplied to the buffer circuit BF1and the inverter circuit IV1. Accordingly, the buffer circuit BF1outputs a low level and the inverter circuit IV1 outputs a high level.Since the output of the inverter circuit IV1 is set to the high level,each of the switches S20 to S23 is turned on. On the other hand, sincethe output of the buffer circuit BF1 is set to the low level, each ofthe switches S30 to S33 is turned off. As a result, the common electrodeTL(0) is connected to the voltage wire 700 via the switches S20 to S23and the ground voltage is supplied thereto. When the common electrodeTL(0) is specified as a non-selected common electrode, since the voltageof the common electrode TL(0) is fixed to the ground voltage, the touchis not detected even if the neighborhood of the common electrode TL(0)is touched.

Since the control signal VCOMSEL is set to the low level in the displayperiod, the switch circuit SW1 is turned off. As a result, the signalwire 800 and the signal line SL(0)2(B) are electrically separated, andthe supply of an image signal to the unit drive electrode driver 12(0)can be prevented. At this time, since the P-type MOSFET TP2 is turnedon, the voltage VGL is supplied to the signal wire 800 via the P-typeMOSFET TP2. As a result, the output of the buffer circuit BF1 is set tothe low level and the output of the inverter circuit IV1 is set to thehigh level. Since the output of the inverter circuit IV1 is set to thehigh level, each of the switches S20 to S23 is turned on. Accordingly,the voltage VCOMDC is supplied to the common electrode TL(p) via theswitches S20 to S23 in the display period. In this case, the voltageVCOMDC is the voltage VCOMDC corresponding to the ground voltage. Inthis manner, the voltage VCOMDC suitable for display can be supplied tothe common electrode TL(0) in the display period.

<Operation of Unit Selection Circuit and Unit Drive Electrode Circuit>

Next, the operation of the liquid crystal display device 1 shown in FIG.8 will be described. FIG. 9A to FIG. 9E are waveform charts showing theoperation of the liquid crystal display device 1 shown in FIG. 8. InFIG. 9, the horizontal axis represents the time and the vertical axisrepresents the voltage. FIG. 9A shows a waveform of the selection signalSEL1, FIG. 9B shows a waveform of the control signal VCOMSEL, and FIG.9C shows a waveform of the control signal TSVCOM.

In FIG. 9, waveforms in the touch detection period and the displayperiod are shown, and waveforms concerning the common electrode TL(0)shown in FIG. 8 are shown for the touch detection period. Namely, FIG.9D shows a waveform of the selection signal TP(0) and FIG. 9E shows awaveform of the drive signal Tx(0) supplied to the common electrodeTL(0). In FIG. 9, “touch detection period (selected common electrode)”indicates the case where the common electrode TL(0) is specified as aselected common electrode by the semiconductor device for touch 7. Also,“touch detection period (non-selected common electrode)” indicates thecase where the common electrode TL(0) is specified as a non-selectedcommon electrode by the semiconductor device for touch 7.

As shown in FIG. 9, the touch detection period and the display periodappear alternately, and though not particularly limited, a signal lineprecharge period is provided before the transition from the touchdetection period to the display period. In the signal line prechargeperiod, the signal lines SL(0) to SL(p) are precharged to set thevoltage of each signal line to a predetermined voltage. Accordingly, theoccurrence of an undesired display can be suppressed in the transitionto the display period.

In the display period, the semiconductor device for touch 7 sets thecontrol signal VCOMSEL to the low level and sets the control signalTSVCOM to the low level. In addition, the semiconductor device for touch7 complementarily sets the selection signals SEL1 and SEL2 to the highlevel. Though FIG. 9A shows only the waveform of the selection signalSEL1, it should be understood that the selection signal SEL2 is at ahigh level when the selection signal SEL1 is at a low level.Accordingly, the switches S11 and S12 shown in FIG. 8 are alternatelyturned on and image signals supplied to the terminals SP11 to SP16 aresupplied to appropriate signal lines in a time-sharing manner.

Further, in the display period, the control signal VCOMSEL is set to alow level, and thus the P-type MOSFET TP2 shown in FIG. 8 is turned onand the switch circuit SW1 is brought out of conduction. Accordingly,the signal wire 800 is separated from the signal line SL(0)2(B) and hasa low-level voltage VGL. Since the low-level voltage VGL is supplied tothe inverter circuit IV1, the switches S20 to S23 are turned on and thevoltage VCOMDC corresponding to the ground voltage is supplied to thecommon electrode TL(0) as a drive voltage for display via the switchesS20 to S23.

Further, since the control signal xVCOMSEL is a signal obtained byinverting the phase of the control signal VCOMSEL, it is at a high levelin the display period. Accordingly, both of the P-type MOSFET TP1 andthe N-type MOSFET TN1 constituting the switch circuit SW2 shown in FIG.8 are turned off and the output node n1 of the switch circuit SW2 is putinto a high-impedance state. Accordingly, an image signal supplied fromthe semiconductor device for driver DDIC to the terminals SP11 to SP16is transmitted to the signal lines SL(0)0(R), SL(0)0(G) and SL(0)0(B) toSL(0)2(R), SL(0)2(G) and SL(0)2(B), and the display in accordance withthe image signal is made.

In the touch detection period, the semiconductor device for driver DDICsets both of the selection signals SEL1 and SEL2 to the high level.Accordingly, both of the switches S11 and S12 shown in FIG. 8 are turnedon. Also, the semiconductor device for touch 7 sets the control signalVCOMSEL to the high level and changes the voltage of the control signalTSVCOM periodically.

When the touch detection period is the touch detection period (selectedcommon electrode), the semiconductor device for touch 7 sets theselection signal TP(0) to the high level. Since the control signalVCOMSEL is at a high level and the control signal xVCOMSEL is at a lowlevel, the switch circuit SW2 is brought into conduction and theselection signal TP(0) at a high level is supplied to the terminal SP16via the switch circuit SW2. At this time, the output terminal (∘ mark inFIG. 7) of the semiconductor device for driver DDIC is in ahigh-impedance state, and thus the selection signal TP(0) supplied tothe terminal SP16 propagates through the control line SS(0) and issupplied to the unit drive electrode circuit UCG1(0).

In the unit drive electrode circuit UCG1(0), the control signal VCOMSELis at a high level, and thus the switch circuit SW1 is brought intoconduction and the P-type MOSFET TP2 is turned off. Therefore, thecontrol line SS(0) is connected to the signal wire 800 via the switchcircuit SW1 and the voltage of the signal wire 800 is set to the highlevel. Since the voltage of the signal wire 800 is set to the highlevel, the output of the buffer circuit BF1 is set to the high level andthe output of the inverter circuit IV1 is set to the low level.Accordingly, the switches S20 to S23 are turned off and the switches S30to S33 are turned on. Since the switches S30 to S33 are turned on, thecommon electrode TL(0) is connected to the signal wire 503 via theswitches S30 to S33. Since the voltage of the control signal TSVCOM inthe signal wire 503 periodically changes, the drive signal Tx(0) whosevoltage changes periodically as shown in FIG. 9E is supplied to thedrive electrode TL(0). Accordingly, as described with reference to FIG.2, whether or not the neighborhood of the drive electrode TL(0) istouched can be detected.

Meanwhile, when the touch detection period is the touch detection period(non-selected common electrode), the semiconductor device for touch 7sets the selection signal TP(0) to the low level. Since the controlsignal VCOMSEL is at a high level and the control signal xVCOMSEL is ata low level, the switch circuit SW2 is brought into conduction and theselection signal TP(0) at a low level is supplied to the terminal SP16via the switch circuit SW2. At this time, since the output terminal (omark in FIG. 7) of the semiconductor device for driver DDIC is in ahigh-impedance state, the selection signal TP(0) supplied to theterminal SP16 propagates through the control line SS(0) and is suppliedto the unit drive electrode circuit UCG1(0).

In the unit drive electrode circuit UCG1, the control signal VCOMSEL isat a high level, and thus the switch circuit SW1 is brought intoconduction and the P-type MOSFET TP2 is turned off. Therefore, thecontrol line SS(0) is connected to the signal wire 800 via the switchcircuit SW1 and the voltage of the signal wire 800 is set to the lowlevel. Since the voltage of the signal wire 800 is set to the low level,the output of the buffer circuit BF1 is set to the low level and theoutput of the inverter circuit IV1 is set to the high level.Accordingly, the switches S30 to S33 are turned off and the switches S20to S23 are turned on. Since the switches S20 to S23 are turned on, thecommon electrode TL(0) is connected to the voltage wire 700 via theswitches S20 to S23. As a result, the control signal TSVCOM whosevoltage changes periodically is not supplied to the common electrodeTL(0) and the voltage VCOMDC corresponding to the ground voltage issupplied thereto. Accordingly, the voltage of a detection signal doesnot change even if the neighborhood of the common electrode TL(0) istouched, and the presence or absence of a touch is not detected.

Although the common electrode TL(0), the unit selection circuit UCG2(0)and the unit drive electrode circuit UCG1(0) have been described as arepresentative example, the configuration and operation are the samealso in the common electrodes TL(1) to TL(p), the unit selectioncircuits UCG2(1) to UCG2(p) and the unit drive electrode circuitsUCG1(1) to UCG1(p).

In the first embodiment, the second circuit CGW2 arranged along theshort side 2-D of the liquid crystal panel 2 can be constituted of asmaller number of elements (P-type MOSFET TP1 and N-type MOSFET TN1),and thus the lower edge frame of the liquid crystal panel 2 can be madenarrower. In addition, since the first circuit (first drive electrodecircuit) CGW1 arranged along the short side 2-U of the liquid crystalpanel 2 drives the common electrodes TL(0) to TL(p), a touch can bedetected. Further, by using the signal line that transmits an imagesignal in the display period as the control line serving as the wirethat transmits the selection signal from the second circuit CGW2 to thefirst circuit CGW1 in the touch detection period, the increase in sizeof the lateral edge frame of the display panel 2 can be suppressed.

In FIG. 7 and FIG. 8, an example in which the signal line SL(0)2(B) isused as the control line SS(0) is described, but the present embodimentis not limited to this. The plurality of signal lines serving as thesignal line SL(0) corresponding to the common electrode TL(0), forexample, all the signal lines SL(0)0(R), SL(0)0(G) and SL(0)0(B) toSL(0)2(R), SL(0)2(G) and SL(0)2(B) or at least some of these signallines may be used as the control line SS(0). In this case, for example,a switch circuit corresponding to the switch circuit SW2 is provided foreach of the terminals SP11 to SP16 to connect an output node n1 of eachof the switch circuits to the terminals SP11 to SP16, and a switchcircuit corresponding to the switch circuit SW1 is provided between eachof the signal lines and the signal wire 800. With respect to each of thesignal lines SL(1) to SL(p), not only one signal line, but also at leastsome of signal lines can be used as the control line like the signalline SL(0).

As described above, with respect to each of the signal lines SL(0) toSL(p) corresponding to a common electrode, the plurality of signal linesare used also as a control line, so that the delay time when theselection signals TP(0) to TP(p) propagate can be reduced.

Second Embodiment

<Configuration of Liquid Crystal Display Device 1>

FIG. 10 is a block diagram showing the configuration of the liquidcrystal display device 1 according to the second embodiment. FIG. 10shows the common electrodes, the first circuit CGW1, the second circuitCGW2 and the semiconductor device for driver DDIC of the module 500shown in FIG. 5 in detail. Though schematically, FIG. 10 is alsodepicted in conformity to an actual arrangement.

The configuration of the liquid crystal display device shown in FIG. 10is similar to the configuration of the liquid crystal display deviceshown in FIG. 7. Here, differences from the liquid crystal displaydevice shown in FIG. 7 will be mainly described. First, an overview ofthe differences will be described. In the liquid crystal display device1 according to the second embodiment, the first circuit CGW1 includes afirst drive electrode circuit like in the first embodiment and thesecond circuit CGW2 also includes a second drive electrode circuit thatsupplies the drive signals Tx(0) to Tx(p) to the common electrodes TL(0)to TL(p). In addition, the liquid crystal display device 1 according tothe second embodiment includes a switching circuit 100 that connects thecommon electrodes TL(0) to TL(p) to the voltage VCOMDC in the displayperiod and connects the common electrodes TL(0) to TL(p) to some of theterminals SP11 to SP16 in the touch detection period.

The first circuit CGW1 is, like in the first embodiment, a first driveelectrode circuit and includes a plurality of first unit drive electrodecircuits UCG1(0) to UCG1(p). These first unit drive electrode circuitsUCG1(0) to UCG1(p) correspond to the common electrodes TL(0) to TL(p) ina one-to-one manner and have the same configuration. When described withusing the first unit drive electrode circuit UCG1(0) as a representativeexample, the first unit drive electrode circuit UCG1(0) includes a firstunit drive electrode driver 12-1(0) and a switch circuit SW3. The firstunit drive electrode driver 12-1(0) has the same configuration as thatof the unit drive electrode driver 12(0) described in the firstembodiment.

The switch circuit SW3 is controlled by the control signal VCOMSEL andtransmits the selection signal supplied via the control line SS(0) tothe signal wire 800 in the touch detection period. Also, the switchcircuit SW3 connects the signal lines other than the signal linecorresponding to the control line SS(0) to the common electrode TL(0) inthe touch detection period.

The second circuit CGW2 is a second drive electrode circuit and includesa plurality of second unit drive electrode circuits UCG2(0) to UCG2(p).These second unit drive electrode circuits UCG2(0) to UCG2(p) correspondto the common electrodes TL(0) to TL(p) in a one-to-one manner and havethe same configuration. When described with using the second unit driveelectrode circuit UCG2(0) as a representative example, the second unitdrive electrode circuit UCG2(0) includes a second unit drive electrodedriver 12-2(0) and the switch circuit SW2. The second unit driveelectrode driver 12-2(0) is similar to the first unit drive electrodedriver 12-1(0) and supplies the control signal TSVCOM whose voltagechanges periodically to the predetermined terminals SP11 to SP15 of theterminals SP11 to SP16 when the selection signal TP(0) specifies thecommon electrode TL(0) as a selected common electrode in the touchdetection period.

The switch circuit SW2 has the same configuration as that of the switchcircuit SW2 described in the first embodiment and supplies the selectionsignal TP(0) to the control line SS(0) in the touch detection period.

The switching circuit 100 is also constituted of a plurality of unitswitching circuits 100(0) to 100(p). The unit switching circuits 100(0)to 100(p) correspond to the common electrodes TL(0) to TL(p) in aone-to-one manner and have the same configuration. When described withusing the unit switching circuit 100(0) as a representative example, theunit switching circuit 100(0) corresponds to the common electrode TL(0)and connects the corresponding common electrode TL(0) to thepredetermined terminals SP11 to SP15 or the voltage VCOMDC in accordancewith the control signal VCOMSEL. Namely, the unit switching circuit100(0) connects the corresponding common electrode TL(0) to the voltageVCOMDC when the control signal VCOMSEL indicates a display period, andit connects the common electrode TL(0) to the terminals SP11 to SP15when the control signal VCOMSEL indicates a touch detection period.

In the touch detection period, the common electrode TL(0) is connectedto the terminals SP11 to SP15 by the unit switching circuit 100(0) and adrive signal from the second unit drive electrode driver 12-2(0) issupplied to the common electrode TL(0) via the terminals SP11 to SP15.At this time, the drive signal from the second unit drive electrodedriver 12-2(0) is supplied also to signal lines other than the signalline SL(0)2(B) corresponding to the control line SS(0).

In the touch detection period, like in the first embodiment, theselection signal TP(0) is supplied to the control line SS(0)[SL(0)2(B)]via the switch circuit SW2. The selection signal TP(0) propagatesthrough the control line SS(0)[SL(0)2(B)] and is supplied to the signalwire 800 via the switch circuit SW3. The first unit drive electrodedriver 12-1(0) forms a drive signal in accordance with the voltage ofthe signal wire 800 and supplies the drive signal to the commonelectrode TL(0) like the drive electrode driver 12(0) in the firstembodiment. At this time, the switch circuit SW3 connects the signallines other than the signal line SL(0)2(B) corresponding to the controlline SS(0) to the common electrode TL(0). Thus, the drive signal formedby the first unit drive electrode driver 12-1(0) is supplied also to thesignal lines other than the signal line SL(0)2(B) corresponding to thecontrol line SS(0).

Accordingly, in the touch detection period, drive signals are suppliedfrom both ends of the common electrode TL(0) by the first unit driveelectrode driver 12-1(0) and the second unit drive electrode driver12-2(0) arranged along the short side 2-U (first side) and the shortside 2-D (second side) of the liquid crystal panel 2. Also, the signallines other than the control line SS(0)[SL(0)2(B)] are connected to thecommon electrode TL(0) in parallel by the switch circuit SW3 and theswitching circuit 100(0), so that combined impedance can be reduced. Asa result, the common electrode TL(0) can be driven even if drivingability of the first unit drive electrode driver 12-1(0) and the secondunit drive electrode driver 12-2(0) are decreased, and the first andsecond unit drive electrode drivers 12-1(0) and 12-2(0) can be reducedin size. Accordingly, the upper and lower edge frames of the liquidcrystal panel 2 can be made narrower.

In addition, since the wire functioning as the signal line SL(0)2(B) inthe display period is used as a control line that transmits theselection signal TP(0) like in the first embodiment, it is possible toprevent the increase in size of the right and left edge frames of theliquid crystal panel 2.

The first unit drive electrode circuit UCG1(0), the second unit driveelectrode circuit UCG2(0) and the unit switching circuit 100(0) havebeen described as a representative example, but the configuration andoperation are the same also in the remaining first unit drive electrodecircuits UCG1(1) to UCG1(p), second unit drive electrode circuitsUCG2(1) to UCG2(p) and unit switching circuits 100(1) to 100(p).

<Configuration of First Unit Drive Electrode Circuit and Second UnitDrive Electrode Circuit>

Next, the configuration of the first unit drive electrode circuitsUCG1(0) to UCG1(p) and the second unit drive electrode circuits UCG2(0)to UCG2(p) shown in FIG. 10 will be described. Here, the first unitdrive electrode circuit UCG1(0) and the second unit drive electrodecircuit UCG2(0) will be described as a representative example withreference to FIG. 11.

FIG. 11 is a circuit diagram showing the configuration of principalparts of the liquid crystal display device 1 according to the secondembodiment. Since the circuit diagram shown in FIG. 11 is similar to thecircuit diagram shown in FIG. 8, differences will be mainly describedhere.

The configuration of the first unit drive electrode driver 12-1(0)included in the first unit drive electrode circuit UCG1(0) is the sameas that of the unit drive electrode driver 12(0) shown in FIG. 8.Namely, the first unit drive electrode driver 12-1(0) includes theP-type MOSFET TP2, the switches S20 to S23 and S30 to S33, the invertercircuit IV1 and the buffer circuit BF1.

The switch circuit SW3 includes switches S40 to S43 controlled by thecontrol signal VCOMSEL. Here, the switch S40 is connected between thesignal wire 800 and the signal line SL(0)2(B) like in FIG. 8. The signalline SL(0)2(B) is used to transmit an image signal in the display periodand is used as the control line SS(0) that transmits a selection signalin the touch detection period like in the first embodiment. The switchS40 is turned off by the control signal VCOMSEL in the display periodand so functions as a separation circuit that separates the signal wire800 and the signal line SL(0)2(B).

The switches S41 to S43 are connected between the common electrode TL(0)and the signal lines other than the signal line SL(0)2(B). FIG. 10 showsthe switches S41 to S43 connected between the common electrode TL(0) andthe signal lines SL(0)0(R), SL(0)0(G) and SL(0)0(B). Each of theswitches S41 to S43 is also turned on when the control signal VCOMSELindicates the touch detection period, that is, when the control signalVCOMSEL is at a high level. On the other hand, when the control signalVCOMSEL indicates the display period, that is, when the control signalVCOMSEL is at a low level, each of the switches S41 to S43 is turnedoff.

In the touch detection period, like in the first embodiment, a selectionsignal is supplied to the signal wire 800 via the control line SS(0) andthe switch S40. When the selection signal specifies the common electrodeTL(0) as a selected common electrode, the selection signal is at a highlevel. Accordingly, like in the case described with reference to FIG. 8,the switches S30 to S33 in the first unit drive electrode driver 12-1(0)are turned on and the control signal TSVCOM is supplied to the commonelectrode TL(0) as the drive signal Tx(0). At this time, since theswitches S41 to S43 in the switch circuit SW3 are also in an on state,the control signal TSVCOM is supplied also to each of the signal linesSL(0)0(R), SL(0)0(G) and SL(0)0(B) via the switches S41 to S43 as thedrive signal Tx(0).

Note that no switch is provided between the signal line SL(0)2(B) usedas the control line SS(0) and the common electrode TL(0). Since thesignal line SL(0)2(B) is used as the control line SS(0) to transmit aselection signal in the touch detection period, no switch is provided soas to prevent the drive signal from being supplied.

Further, when the selection signal specifies the common electrode TL(0)as a non-selected common electrode in the touch detection period, theselection signal is set to the low level. Accordingly, like in the casedescribed with reference to FIG. 8, the switches S20 to S23 in the firstunit drive electrode driver 12-1(0) are turned on. Accordingly, thevoltage VCOMDC corresponding to the ground voltage is supplied to thecommon electrode TL(0) and the signal lines SL(0)0(R), SL(0)0(G) andSL(0)0(B).

Since the control signal VCOMSEL is set to the low level in the displayperiod, the switches S40 to S43 in the switch circuit SW3 are turnedoff. Accordingly, the signal line SL(0)2(B) is separated from the signalwire 800, and the switches S20 to S23 are turned on and a drive voltagefor display is supplied from the first unit drive electrode circuitUCG1(0) to the common electrode TL(0) like in the case described withreference to FIG. 8.

The second unit drive electrode circuit UCG2(0) includes the second unitdrive electrode driver 12-2(0) and the switch circuit SW2. The switchcircuit SW2 has the same configuration as that of the switch circuit SW2shown in FIG. 8. Namely, the switch circuit SW2 includes the N-typeMOSFET TN1 controlled by the control signal VCOMSEL and the P-typeMOSFET TP1 controlled by the control signal xVCOMSEL. The selectionsignal TP(0) from the semiconductor device for touch 7 is supplied tothe input node n2 of the switch circuit SW2 and the output node n1 ofthe switch circuit SW2 is connected to the terminal SP16.

The second unit drive electrode driver 12-2(0) includes a first switchconnected between each of the terminals SP11 to SP16 and the signal wire503 and a second switch connected between each of the terminals SP11 toSP16 and the voltage wire 700. FIG. 11 shows first switches S60 to S63connected between the terminals SP11 to SP13 and SP16 and the signalwire 503 and second switches S70 to S73 connected between the terminalsSP11 to SP13 and SP16 and the voltage wire 700 of these first switchesand second switches. In addition, the second unit drive electrodecircuit UCG2(0) includes an inverter circuit IV2 to which the selectionsignal TP(0) from the semiconductor device for touch 7 is supplied, abuffer circuit BF2 to which the selection signal TP(0) is supplied, anda 2-input AND circuit ND1 that receives the output of the invertercircuit IV2 and the control signal VCOMSEL. The buffer circuit BF2outputs a switch control signal SW1_C in phase with the selection signalTP(0). The inverter circuit IV2 forms an inverted signal obtained byinverting the phase of the selection signal TP(0). The 2-input ANDcircuit ND1 receives the control signal VCOMSEL and the inverted signaland outputs a switch control signal SW2_C.

Among the first switches, the first switches (S60 to S62 in FIG. 11)connected between the terminals other than the terminal SP16 (SP11 toSP13 in FIG. 11) and the signal wire 503 are controlled by the switchcontrol signal SW1_C. Also, among the second switches, the secondswitches (S70 to S72 in FIG. 11) connected between the terminals otherthan the terminal SP16 (SP11 to SP13 in FIG. 11) and the voltage wire700 are controlled by the switch control signal SW2_C. Meanwhile, thefirst switch S63 connected between the terminal SP16 and the signal wire503 is configured to be always turned off. In addition, the secondswitch S73 connected between the terminal SP16 and the voltage wire 700is also configured to be always turned off. For example, a low-levelcontrol signal is made to be always supplied to the first switch S63 andthe second switch S73.

The second unit drive electrode driver 12-2(0) operates in the samemanner as the unit drive electrode driver 12(0) described with referenceto FIG. 8. Namely, when the voltage of the selection signal TP(0) is ata high level in the touch detection period, the buffer circuit BF2outputs the switch control signal SW1_C at a high level. At this time,the inverter circuit IV2 outputs an inverted signal at a low level.Since the control signal VCOMSEL is set to the high level in the touchdetection period, the 2-input AND circuit ND1 outputs the invertedsignal from the inverter circuit IV2 as the switch control signal SW2_C.Namely, the 2-input AND circuit ND1 outputs the switch control signalSW2 C at a low level. Accordingly, the first switches other than thefirst switch S63 (S60 to S62) are turned on and the second switches (S70to S72) are turned off. On the other hand, when the voltage of theselection signal TP(0) is at a low level, the buffer circuit BF2 outputsthe switch control signal SW1_C at a low level and the inverter circuitIV2 outputs an inverted signal at a high level. The 2-input AND circuitND1 outputs the high-level inverted signal as the switch control signalSW2_C. Accordingly, the second switches other than the second switch S73(S70 to S72) are turned on and the first switches (S60 to S62) areturned off.

As described above, when the common electrode TL(0) is specified as aselected common electrode, the semiconductor device for touch 7 sets theselection signal TP(0) corresponding to the common electrode TL(0) tothe high level. Meanwhile, when the common electrode TL(0) is specifiedas a non-selected common electrode, the semiconductor device for touch 7sets the selection signal TP(0) corresponding to the common electrodeTL(0) to the low level. As a result, when the common electrode TL(0) isspecified as a selected common electrode, the first switches other thanthe switch S63 (S60 to S62) are turned on and the control signal TSVCOMwhose voltage changes periodically is supplied to the terminals SP11 toSP15 as a drive signal via these first switches. Meanwhile, when thecommon electrode TL(0) is specified as a non-selected common electrode,the second switches other than the switch S73 (S70 to S72) are turned onand the voltage VCOMDC corresponding to the ground voltage is suppliedfrom the voltage wire 700 to the terminals SP11 to SP15 via these secondswitches.

In the touch detection period, as described with reference to FIG. 8,the switch circuit SW2 is turned on. Thus, the selection signal TP(0)supplied to the input node n2 of the switch circuit SW2 is supplied tothe terminal SP16 via the switch circuit SW2.

Namely, when the selection signal TP(0) is at a high level in the touchdetection period, the voltage of the terminals SP11 to SP15 changes inaccordance with the change of the voltage of the control signal TSVCOMand the terminal SP16 has a voltage corresponding to the voltage of theselection signal TP(0).

The unit switching circuit 100(0) includes a plurality of third switchescontrolled by the control signal VCOMSEL. Here, the third switch is a2-input switch having a common terminal C and two input terminals P1 andP2 and connects the common terminal C to the input terminal P1 or P2 inaccordance with the voltage of the control signal VCOMSEL. The commonterminal C of each of the plurality of third switches is connected tothe common electrode TL(0) and the input terminal P1 of each of them isconnected to a voltage wire 111 to which the voltage VCOMDC is supplied.The input terminal P2 of the third switch is connected to the terminalsSP11 to SP16. In FIG. 11, among the third switches, the third switcheswhose input terminals P2 are connected to the terminals SP11 to SP13 andSP16 are denoted as S50 to S53. In the second embodiment, among thethird switches connected to the terminals SP11 to SP16, the third switchS53 whose input terminal P2 is connected to the terminal SP16 iscontrolled so that the common terminal C is always connected to theinput terminal P1 regardless of the voltage of the control signalVCOMSEL.

In the second embodiment, the third switch connects the common terminalC to the input terminal P1 when the control signal VCOMSEL is at a lowlevel, and it connects the common terminal C to the input terminal P2when the control signal VCOMSEL is at a high level. Incidentally, forexample, a low-level control signal is always supplied to the thirdswitch S53 among the third switches.

Accordingly, since the control signal VCOMSEL is set to the high levelin the touch detection period, the common terminal C is connected to thecorresponding terminals SP11 to SP15 via the input terminal P2 in thethird switches other than the third switch S53 (S50 to S52). Namely, inthe touch detection period, the common electrode TL(0) is connected tothe terminals SP11 to SP15. As described in the first embodiment, theswitches S11 and S12 in the unit signal line selector 6(0) are bothturned on in the touch detection period.

Thus, in the touch detection period, the drive signal supplied from thesecond unit drive electrode driver 12-2(0) to the terminals SP11 to SP15is supplied to the signal lines other than the signal line SL(0)2(B)functioning as the control line SS(0) and the common electrode TL(0).

Also, since the common electrode TL(0) is connected to the voltage wire700 via the third switches S50 to S53 in the display period, a drivevoltage for display can be provided to the common electrode TL(0). Inthe display period, the semiconductor device for touch 7 sets theselection signals TP(0) to TP(p) to the low level. In addition, thecontrol signal VCOMSEL is set to the low level. Accordingly, the switchcontrol signal SW1_C at a low level is output from the buffer circuitBF2 and the switch control signal SW2_C at a low level is output alsofrom the 2-input AND circuit ND1. As a result, the first switches S60 toS62 and the second switches S70 to S72 are turned off and the output ofthe second unit drive electrode driver 12-2(0) is put into ahigh-impedance state. Accordingly, the image signal supplied from thesemiconductor device for driver DDIC to the terminals SP11 to SP16 issupplied to the unit signal line selector 6(0) and is then supplied toan appropriate signal line.

In the second embodiment, the first switch S63, the second switch S73and the third switch S53 do not function as a switch. Therefore, thefirst switch S63 and the second switch S73 do not have to be provided.Further, the third switch S53 may be a wire connecting the commonelectrode TL(0) and the voltage wire 700. However, by providing thefirst switch S63, the second switch S73 and the third switch S53, thesecond unit drive electrode driver 12-2(0) and the switching circuit100(0) can be constituted by repeatedly arranging the first switch,second switch and third switch, so that the design and manufacture canbe facilitated. When viewed from the viewpoint of not functioning as aswitch, each of the first switch S63, the second switch S73 and thethird switch S53 can be regarded as a dummy switch.

The first unit drive electrode circuit UCG1(0) and the second unit driveelectrode circuit UCG2(0) have been described as a representativeexample, but the same is true of the remaining first unit driveelectrode circuits UCG1(1) to UCG1(p) and second unit drive electrodecircuits UCG2(1) to UCG2(p).

<Operation of First Unit Drive Electrode Circuit and Second Unit DriveElectrode Circuit>

Next, the operation of the liquid crystal display device 1 shown in FIG.11 will be described. FIG. 12A to FIG. 12E are waveform charts showingthe operation of the liquid crystal display device 1 shown in FIG. 11.In FIG. 12, the horizontal axis represents the time and the verticalaxis represents the voltage. FIG. 12A shows a waveform of the selectionsignal SEL1, FIG. 12B shows a waveform of the control signal VCOMSEL,and FIG. 12C shows a waveform of the control signal TSVCOM.

In FIG. 12, waveforms in the touch detection period and the displayperiod are shown, and waveforms concerning the common electrode TL(0)shown in FIG. 11 are shown for the touch detection period. Namely, FIG.12D shows a waveform of the selection signal TP(0) and FIG. 12E shows awaveform of the drive signal Tx(0) supplied to the common electrodeTL(0). In FIG. 12, “touch detection period (selected common electrode)”indicates the case where the common electrode TL(0) is specified as aselected common electrode by the semiconductor device for touch 7. Also,“touch detection period (non-selected common electrode)” indicates thecase where the common electrode TL(0) is specified as a non-selectedcommon electrode by the semiconductor device for touch 7.

In FIG. 12, operations in the signal line precharge period and thedisplay period are almost the same as those described with reference toFIG. 9, and thus only differences will be described. In the firstembodiment, the voltage VCOMDC corresponding to the ground voltage issupplied from the unit drive electrode circuit UCG1(0) to the commonelectrode TL(0) in the signal line precharge period and the displayperiod. On the other hand, in the second embodiment, the voltage VCOMDCcorresponding to the ground voltage is supplied to the common electrodeTL(0) from both of the first unit drive electrode circuit UCG1(0) andthe unit switching circuit 100(0). Accordingly, the voltage of thecommon electrode TL(0) for display can be more stabilized.

In the touch detection period, the semiconductor device for driver DDICsets both of the selection signals SEL1 and SEL2 to the high level.Accordingly, both of the switches S11 and S12 shown in FIG. 11 areturned on. Also, the semiconductor device for touch 7 sets the controlsignal VCOMSEL to the high level and changes the voltage of the controlsignal TSVCOM periodically.

When the touch detection period is the touch detection period (selectedcommon electrode), the semiconductor device for touch 7 sets theselection signal TP(0) to the high level. Since the control signalVCOMSEL is at a high level and the control signal xVCOMSEL is at a lowlevel, the switch circuit SW2 is brought into conduction and theselection signal TP(0) at a high level is supplied to the terminal SP16via the switch circuit SW2. At this time, the output terminal (o mark inFIG. 7) of the semiconductor device for driver DDIC is in ahigh-impedance state, and thus the selection signal TP(0) supplied tothe terminal SP16 propagates through the control line SS(0)[SL(0)2(B)]and is supplied to the first unit drive electrode circuit UCG1(0).

In the first unit drive electrode circuit UCG1(0), the control signalVCOMSEL is at a high level, and thus the switches S40 to S43 in theswitch circuit SW3 are brought into conduction and the P-type MOSFET TP2is turned off. Therefore, the control line SS(0) is connected to thesignal wire 800 via the switch S40 and the voltage of the signal wire800 is set to the high level. Since the voltage of the signal wire 800is set to the high level, the output of the buffer circuit BF1 is set tothe high level and the output of the inverter circuit IV1 is set to thelow level. Accordingly, the switches S20 to S23 are turned off and theswitches S30 to S33 are turned on. Since the switches S30 to S33 areturned on, the common electrode TL(0) is connected to the signal wire503 via the switches S30 to S33. Since the voltage of the control signalTSVCOM in the signal wire 503 periodically changes, the drive signalTx(0) whose voltage changes periodically as shown in FIG. 11E issupplied to the drive electrode TL(0).

Also, since the selection signal TP(0) is at a high level, the switchcontrol signal SW1_C which is an output signal of the buffer circuit BF2in the second unit drive electrode circuit UCG2(0) is set to the highlevel. At this time, an inverted signal output from the inverter circuitIV2 is set to the low level and the switch control signal SW2_C at a lowlevel is output from the 2-input AND circuit ND1. Accordingly, the firstswitches (S60 to S62) are turned on and the second switches (S70 to S72)are turned off. Consequently, the control signal TSVCOM whose voltagechanges periodically is supplied to the terminals SP11 to SP15 via thefirst switches.

Since the control signal VCOMSEL is at a high level as shown in FIG.12B, the common terminal C of the third switches (S50 to S52) in theunit switching circuit 100(0) is connected to the input terminal P2.Thus, the control signal TSVCOM supplied to the terminals SP11 to SP15is supplied to the common electrode TL(0) via the third switches. Also,since the switches S11 and S12 in the unit signal line selector 6(0) arein an on state, the control signal TSVCOM is supplied also to the signallines other than the signal line SL(0)2(B) functioning as the controlline SS(0).

Accordingly, the control signal TSVCOM is supplied as the drive signalTx(0) to the common electrode TL(0) from both ends thereof, and whetheror not the neighborhood of the drive electrode TL(0) is touched can bedetected as described with reference to FIG. 2.

Meanwhile, when the touch detection period is the touch detection period(non-selected common electrode), the semiconductor device for touch 7sets the selection signal TP(0) to the low level. Since the controlsignal VCOMSEL is at a high level and the control signal xVCOMSEL is ata low level, the switch circuit SW2 is brought into conduction and theselection signal TP(0) at a low level is supplied to the terminal SP16via the switch circuit SW2. At this time, since the output terminal (∘mark in FIG. 7) of the semiconductor device for driver DDIC is in ahigh-impedance state, the selection signal TP(0) supplied to theterminal SP16 propagates through the control line SS(0) and is suppliedto the first unit drive electrode circuit UCG1(0).

In the first unit drive electrode circuit UCG1, the control signalVCOMSEL is at a high level, and thus the switches S40 to S43 in theswitch circuit SW3 are brought into conduction and the P-type MOSFET TP2is turned off. Therefore, the control line SS(0) is connected to thesignal wire 800 via the switch circuit SW1 and the voltage of the signalwire 800 is set to the low level. Since the voltage of the signal wire800 is set to the low level, the output of the buffer circuit BF1 is setto the low level and the output of the inverter circuit IV1 is set tothe high level. Accordingly, the switches S30 to S33 are turned off andthe switches S20 to S23 are turned on. Since the switches S20 to S23 areturned on, the common electrode TL(0) is connected to the voltage wire700 via the switches S20 to S23. As a result, the control signal TSVCOMwhose voltage changes periodically is not supplied to the commonelectrode TL(0) and the voltage VCOMDC corresponding to the groundvoltage is supplied thereto.

In the second unit drive electrode circuit UCG2(0), the selection signalTP(0) is set to the low level, and thus the buffer circuit BF2 outputsthe switch control signal SW1_C at a low level. Also, the invertercircuit IV2 outputs a high-level inverted signal. At this time, thecontrol signal VCOMSEL is at a high level, and thus the 2-input ANDcircuit ND1 outputs the switch control signal SW2_C at a high level.

Accordingly, the first switches (S60 to S62) are turned off and thesecond switches (S70 to S72) are turned on. Since the second switchesare turned on, the voltage VCOMDC corresponding to the ground voltage issupplied to the terminals SP11 to SP15 via the second switches.Accordingly, the voltage VCOMDC is supplied to the common electrodeTL(0) and the signal lines other than the signal line corresponding tothe control line SS(0).

Also in this case, the voltage VCOMDC is supplied at both ends of thecommon electrode TL(0), and thus the voltage of the common electrodeTL(0) can be more stabilized. Since the fixed voltage (VCOMDC) issupplied to the common electrode TL(0), the voltage of a detectionsignal does not change even if the neighborhood of the common electrodeTL(0) is touched, and the presence or absence of a touch is notdetected.

The common electrode TL(0), the first unit drive electrode circuitUCG1(0) and the second unit drive electrode circuit UCG2(0) have beendescribed as a representative example, but the configuration andoperation are the same also in the remaining common electrodes TL(1) toTL(p), first unit drive electrode circuits UCG1(1) to UCG1(p) and secondunit drive electrode circuits UCG2(1) to UCG2(p).

In the second embodiment, the common electrodes TL(0) to TL(p) aredriven by both of the first drive electrode circuit CGW1 and the seconddrive electrode circuit CGW2 arranged along the short sides 2-U and 2-Dof the liquid crystal panel 2. Thus, the common electrodes can be driveneven if driving ability of each of the first drive electrode circuitCGW1 and the second drive electrode circuit CGW2 is decreased, so thatthe lower and upper edge frames of the liquid crystal panel 2 can bemade narrower. Also, by using the signal line that transmits an imagesignal in the display period as the control line serving as the wirethat transmits the selection signal from the second drive electrodecircuit CGW2 to the first drive electrode circuit CGW1 in the touchdetection period, the increase in size of the lateral edge frame of thedisplay panel 2 can be suppressed.

In FIG. 10 to FIG. 12, the example in which the signal line SL(0)2(B) isused as the control line SS(0) has been described, but the presentembodiment is not limited to this. At least some of the signal lines canbe used as a control line.

Third Embodiment

<Configuration of Liquid Crystal Display Device 1>

FIG. 13 is a block diagram showing the configuration of the liquidcrystal display device 1 according to the third embodiment. FIG. 13shows the common electrodes, the first circuit CGW1, the second circuitCGW2 and the semiconductor device for driver DDIC of the module 500shown in FIG. 5 in detail. Though schematically, FIG. 13 is alsodepicted in conformity to an actual arrangement.

The configuration of the liquid crystal display device shown in FIG. 13is similar to the configuration of the liquid crystal display deviceshown in FIG. 10. Here, differences from the liquid crystal displaydevice shown in FIG. 10 will be mainly described. First, an overview ofthe differences will be described. In the liquid crystal display device1 according to the third embodiment, the semiconductor device for touch7 supplies a selection signal whose voltage changes periodically to thecommon electrode specified as a selected common electrode and supplies aselection signal whose voltage value does not change temporally to thecommon electrode specified as a non-selected common electrode in thetouch detection period. Each of the first circuit CGW1 and the secondcircuit CGW2 includes a drive electrode circuit which, when a selectionsignal that changes periodically is supplied, alternately connects thecommon electrode corresponding to the selection signal to a firstvoltage (TPH) and a second voltage (VCOMDC) in synchronization with theselection signal. Here, like in the second embodiment, the first circuitCGW1 is referred to as the first drive electrode circuit CGW1 and thesecond circuit CGW2 is referred to as the second drive electrode circuitCGW2.

The first drive electrode circuit CGW1 includes a plurality of firstunit drive electrode circuits UCG1(0) to UCG1(p) like in the secondembodiment. These first unit drive electrode circuits UCG1(0) to UCG1(p)correspond to the common electrodes TL(0) to TL(p) in a one-to-onemanner and have the same configuration. When described with using thefirst unit drive electrode circuit UCG1(0) as a representative example,the first unit drive electrode circuit UCG1(0) includes the first unitdrive electrode driver 12-1(0) and a switch circuit SW4. When the commonelectrode TL(0) is specified as a selected common electrode, the firstunit drive electrode driver 12-1(0) alternately connects the commonelectrode TL(0) to a first voltage wire 1300 and a second voltage wire700 in synchronization with voltage change of the selection signalsupplied via the signal wire 800. Here, the first voltage TPH at a highlevel is supplied to the first voltage wire 1300 and the second voltageVCOMDC corresponding to the ground voltage is supplied to the secondvoltage wire 700. The first voltage TPH is a voltage with a highervoltage value than the second voltage VCOMDC.

The switch circuit SW4 is controlled by the control signal VCOMSEL andtransmits the selection signal supplied via the signal line SL(0) to thesignal wire 800 in the touch detection period. FIG. 13 shows the signallines SL(0)0(R), SL(0)0(B), SL(0)2(R) and SL(0)2(B) as the signal lineSL(0).

The second drive electrode circuit CGW2 also includes a plurality ofsecond unit drive electrode circuits UCG2(0) to UCG2(p). These secondunit drive electrode circuits UCG2(0) to UCG2(p) correspond to thecommon electrodes TL(0) to TL(p) in a one-to-one manner and have thesame configuration. When described with using the second unit driveelectrode circuit UCG2(0) as a representative example, when theselection signal TP(0) specifies the common electrode TL(0) as aselected common electrode in the touch detection period, the second unitdrive electrode circuit UCG2(0) alternately connects the terminals SP11to SP16 to the first voltage wire 1300 and the second voltage wire 700in synchronization with voltage change of the selection signal TP(0).The unit signal line selector 6(0) connects the terminals SP11 to SP16to the common electrode TL(0) and the signal line SL(0) in the touchdetection period like in the second embodiment. Thus, the second unitdrive electrode circuit UCG2(0) can be regarded as a second driveelectrode driver.

The first unit drive electrode circuit UCG1(0) and the second unit driveelectrode circuit UCG2(0) have been described as a representativeexample, but the configuration and operation are the same also in theremaining first unit drive electrode circuits UCG1(1) to UCG1(p) andsecond unit drive electrode circuits UCG2(1) to UCG2(p).

<Configuration of First Unit Drive Electrode Circuit and Second UnitDrive Electrode Circuit>

Next, the configuration of the first unit drive electrode circuitsUCG1(0) to UCG1(p) and the second unit drive electrode circuits UCG2(0)to UCG2(p) shown in FIG. 13 will be described. Here, the first unitdrive electrode circuit UCG1(0) and the second unit drive electrodecircuit UCG2(0) will be described as a representative example withreference to FIG. 14.

FIG. 14 is a circuit diagram showing the configuration of principalparts of the liquid crystal display device 1 according to the thirdembodiment. Since the configuration of the circuit shown in FIG. 14 issimilar to the configuration of the circuit shown in FIG. 11,differences will mainly be described here.

In the second embodiment, each of the first unit drive electrode circuitUCG1(0) and the second unit drive electrode circuit UCG2(0) operates tosupply the control signal TSVCOM whose voltage changes periodically tothe common electrode TL(0) when the selection signal TP(0) is at a highlevel. Meanwhile, in the third embodiment, when the voltage of theselection signal TP(0) changes periodically, the common electrode TL(0)is alternately connected to the first voltage wire 1300 and the secondvoltage wire 700 in synchronization with the voltage change.Accordingly, even if the driving ability of the circuit that forms thecontrol signal TSVCOM is low, the voltage of the selected commonelectrode can be changed within a desired time.

First, the first unit drive electrode circuit UCG1(0) will be described.The configuration of the first unit drive electrode driver 12-1(0)included in the first unit drive electrode circuit UCG1(0) is similar tothat of the first unit drive electrode driver 12(0) shown in FIG. 11.Namely, the first unit drive electrode driver 12-1(0) includes theP-type MOSFET TP2, the switches S20 to S23 and S30 to S33, the invertercircuit IV1 and the buffer circuit BF1. In FIG. 11, the switches S30 toS33 are connected between the common electrode TL(0) and the signal wire503. In the third embodiment, however, the switches S30 to S33 areconnected between the common electrode TL(0) and the first voltage wire1300.

The switch circuit SW4 included in the first unit drive electrodecircuit UCG1(0) includes switches S40-1 to S40-4 controlled by thecontrol signal VCOMSEL. Here, the switches S40-1 to S40-4 are connectedbetween the signal wire 800 and the signal line SL(0). FIG. 14 shows thesignal lines SL(0)0(R), SL(0)0(G), SL(0)0(B) and SL(0)2(B) as examplesof the signal line SL(0). These signal lines SL(0)0(R), SL(0)0(G),SL(0)0(B) and SL(0)2(B) are used to transmit an image signal in thedisplay period and are used as signal lines that transmit a selectionsignal in the touch detection period like in the second embodiment. Theswitches S40-1 to S40-4 are turned off by the control signal VCOMSEL inthe display period and so function as a separation circuit thatseparates the signal wire 800 and the signal lines SL(0)0(R), SL(0)0(G),SL(0)0(B) and SL(0)2(B). When viewed from the viewpoint of transmittinga selection signal, the signal lines SL(0)0(R), SL(0)0(G), SL(0)0(B) andSL(0)2(B) can be regarded as constituting the control line SS(0).

In the touch detection period, a selection signal is supplied to thesignal wire 800 via the signal lines SL(0)0(R), SL(0)0(G), SL(0)0(B) andSL(0)2(B) and the switches S40-1 to S40-4 like in the second embodiment.

Next, the second unit drive electrode circuit UCG2(0) will be described.The second unit drive electrode circuit UCG2(0) includes a plurality offourth switches connected between the terminals SP11 to SP16 and thefirst voltage wire 1300 and a plurality of fifth switches connectedbetween the terminals SP11 to SP16 and the second voltage wire 700. Inaddition, the second unit drive electrode circuit UCG2(0) includes aninverter circuit IV3, a buffer circuit BF3 and a 2-input AND circuitND2. The buffer circuit BF3 and the inverter circuit IV3 receive theselection signal TP(0) from the semiconductor device for touch 7 and thebuffer circuit BF3 outputs a signal in phase with the selection signalTP(0) as a switch control signal SW3_C. Also, the inverter circuit IV3inverts the phase of the selection signal TP(0) and supplies theinverted signal to the 2-input AND circuit ND2. The 2-input AND circuitND2 receives the inverted signal and the control signal VCOMSEL andoutputs a switch control signal SW4_C.

In FIG. 14, switches S80 to S83 connected between the terminals SP11 toSP13 and SP16 and the first voltage wire 1300 are shown as the fourthswitches. Also, switches S90 to S93 connected between the terminals SP11to SP13 and SP16 and the second voltage wire 700 are shown as the fifthswitches. The fourth switches S80 to S83 are controlled by the switchcontrol signal SW3_C and the fifth switches S90 to S93 are controlled bythe switch control signal SW4_C.

In the touch detection period, the control signal VCOMSEL is set to thehigh level. When the semiconductor device for touch 7 specifies thecommon electrode TL(0) as a selected common electrode, the semiconductordevice for touch 7 changes the voltage of the selection signal TP(0)periodically. Accordingly, the voltage of the switch control signalSW3_C output from the buffer circuit BF3 changes periodically. Also,since the control signal VCOMSEL at a high level is supplied, the2-input AND circuit ND2 outputs a signal obtained by inverting the phaseof the selection signal TP(0) as the switch control signal SW4_C.Accordingly, the fourth switches (S80 to S83) and the fifth switches(S90 to S93) are alternately turned on. As a result, the terminals SP11to SP16 are alternately connected to the first voltage wire 1300 and thesecond voltage wire 700 via the fourth switches and the fifth switches.

Meanwhile, when the semiconductor device for touch 7 specifies thecommon electrode TL(0) as a non-selected common electrode, thesemiconductor device for touch 7 outputs the selection signal TP(0) at alow level. In this case, the switch control signal SW3_C is set to a lowlevel, the switch control signal SW4_C is set to a high level, and therespective voltage values are maintained. As a result, the fourthswitches (S80 to S83) are turned off and the fifth switches (S90 to S93)are turned on. Thus, the terminals SP11 to SP16 are connected to thesecond voltage wire 700 via the fifth switches.

The unit switching circuit 100(0) is constituted of a plurality of thirdswitches like in the second embodiment. FIG. 14 shows the switches S50to S53 as the third switches like in the second embodiment. In the thirdembodiment, each of the third switches connects the common electrodeTL(0) to the signal line SL(0) or the terminals SP11 to SP16 inaccordance with the control signal VCOMSEL unlike in the secondembodiment. Namely, in the second embodiment, the third switch S53functions as a dummy switch as shown in FIG. 11, but in the thirdembodiment, the third switch S53 functions as a switch whose commonterminal C is connected to the voltage wire 700 or the terminal SP16 viathe input terminal P1 or P2 in accordance with the control signalVCOMSEL.

As described in the first and second embodiments, the selection signalsSEL1 and SEL2 complementarily turn on the switches S11 and S12constituting the unit signal line selector 6(0) in the display period.Accordingly, an image signal supplied to the terminals SP11 to SP16 issupplied to the appropriate signal line SL(0) by the unit signal lineselector 6(0). Meanwhile, in the touch detection period, each of theselection signals SEL1 and SEL2 is set to the high level. As a result,the switches S11 and S12 constituting the unit signal line selector 6(0)are both turned on.

In the display period, an image signal is supplied from thesemiconductor device for driver DDIC to the terminals SP11 to SP16 likein the second embodiment. Meanwhile, in the touch detection period, thesemiconductor device for driver DDIC puts the output terminal thereof (∘mark in FIG. 13) into a high-impedance state. Since the control signalVCOMSEL is set to the high level, the common terminal C of each of thethird switches S50 to S53 constituting the unit switching circuit 100(0)is connected to the input terminal P2 in the touch detection period.Further, in this period, each of the switches S11 and S12 of the unitsignal line selector 6(0) is turned on.

Thus, when the voltage of the selection signal TP(0) changesperiodically in the touch detection period, the terminals SP11 to SP16,the common electrode TL(0) and the signal line SL(0) are alternatelyconnected to the first voltage wire 1300 and the second voltage wire 700in synchronization with voltage change of the selection signal TP(0) andthe voltages thereof change. In other words, the drive signal Tx(0) inaccordance with the selection signal TP(0) is supplied to the terminalsSP11 to SP16, the common electrode TL(0) and the signal line SL(0). Thechange of the voltage in the signal line SL(0) is supplied to the signalwire 800 via the switches S40-1 to S40-4. In other words, the drivesignal Tx(0) formed by the second unit drive electrode circuit UCG2(0)is supplied to the first unit drive electrode circuit UCG1(0) as aselection signal and is then supplied to the drive electrode driver12-1(0) included in the first unit drive electrode circuit UCG1(0).

With the change of the voltage in the signal wire 800, the switches S30to S33 and the switches S20 to S23 constituting the first unit driveelectrode driver 12-1(0) are alternately turned on. The switches S30 toS33 are connected between the first voltage wire 1300 and the commonelectrode TL(0) and the switches S20 to S23 are connected between thesecond voltage wire 700 and the common electrode TL(0). Accordingly, thefirst unit drive electrode circuit UCG1(0) also supplies the drivesignal Tx(0) to the corresponding common electrode TL(0) insynchronization with the voltage change of the selection signal TP(0).Namely, the drive signal Tx(0) is supplied to the common electrode TL(0)from the first unit drive electrode circuit UCG1(0) and the second unitdrive electrode circuit UCG2(0) arranged at both ends thereof, so thatthe common electrode TL(0) is driven. Naturally, the drive signal Tx(0)from the first unit drive electrode circuit UCG1(0) and the drive signalTx(0) from the second unit drive electrode circuit UCG2(0) are in phasewith each other.

Meanwhile, when the selection signal TP(0) specifies the commonelectrode TL(0) as a non-selected common electrode in the touchdetection period, that is, when the selection signal TP(0) is maintainedat the ground voltage, the fifth switches (S90 to S93) are turned on inthe second unit drive electrode circuit UCG2(0), and the fourth switches(S80 to S83) are turned off. Accordingly, the second voltage VCOMDC inthe second voltage wire 700 is supplied to the terminals SP11 to SP16,the common electrode TL(0) and the signal line SL(0) via the fifthswitches (S90 to S93). The second voltage VCOMDC in the signal lineSL(0) is supplied to the signal wire 800 via the switches S40-1 toS40-4. Accordingly, the switches S20 to S23 in the drive electrodedriver 12-1(0) are turned on, so that the second voltage VCOMDC issupplied also from the first unit drive electrode circuit UCG1(0) to thecommon electrode TL(0) via the second voltage wire 700.

In the display period, the semiconductor device for touch 7 sets each ofthe selection signals TP(0) to TP(p) to the low level. At this time, thecontrol signal VCOMSEL is set to the low level. As a result, the fourthswitches (S80 to S83) and the fifth switches (S90 to S93) in the secondunit drive electrode circuit UCG2(0) are turned off. Accordingly, theoutput of the second unit drive electrode circuit UCG2(0) is put into ahigh-impedance state. Meanwhile, since the common terminal C of thethird switches (S50 to S53) constituting the unit switching circuit100(0) is connected to the input terminal P1 by the control signalVCOMSEL at a low level in the display period, the common electrode TL(0)is connected to the second voltage wire 700 by the unit switchingcircuit 100(0). At this time, the P-type MOSFET TP2 in the first unitdrive electrode circuit UCG1(0) is also turned on, and thus the switchesS20 to S23 in the drive electrode driver 12-1(0) are also turned on.Therefore, the second voltage VCOMDC is supplied to the common electrodeTL(0) also from the first unit drive electrode circuit UCG1(0).

As a result, in the display period, the second voltage VCOMDC issupplied from both ends of the common electrode TL(0) by the first unitdrive electrode circuit UCG1(0) and the unit switching circuit 100(0).In addition, the image signal displayed in the display period issupplied from the semiconductor device for driver DDIC to the terminalsSP11 to SP16 and is then transmitted to the signal line SL(0).

As described above, since the drive signal Tx(0) is supplied from bothends of the drive electrode TL(0) in the touch detection period, thefirst unit drive electrode circuit UCG1(0) and the second unit driveelectrode circuit UCG2(0) can be reduced in size, and the reduction inwidth of the upper and lower edge frames can be achieved. In addition,since the signal line that transmits an image signal in the displayperiod is used as a control line that transmits a selection signal inthe touch detection period, it is possible to suppress the increase insize of the right and left edge frames. Further, since the secondvoltage VCOMDC which is a drive voltage for display is supplied fromboth ends of the drive electrode TL(0) in the display period, thevoltage of the common electrode in the display period can be stabilized.

<Operation of First Unit Drive Electrode Circuit and Second Unit DriveElectrode Circuit>

Next, the operation of the liquid crystal display device 1 shown in FIG.14 will be described. FIG. 15A to FIG. 15E are waveform charts showingthe operation of the liquid crystal display device 1 shown in FIG. 14.In FIG. 15, the horizontal axis represents the time and the verticalaxis represents the voltage. FIG. 15A shows a waveform of the selectionsignal SEL1, FIG. 15B shows a waveform of the control signal VCOMSEL,and FIG. 15C shows a waveform of the selection signal TP(0).

FIG. 15D shows a waveform of the switch control signal SW3_C thatcontrols the fourth switches and FIG. 15E shows a waveform of the switchcontrol signal SW4_C that controls the fifth switches. In FIG. 15,“touch detection period (selected common electrode)” indicates the casewhere the common electrode TL(0) is specified as a selected commonelectrode by the semiconductor device for touch 7. Also, “touchdetection period (non-selected common electrode)” indicates the casewhere the common electrode TL(0) is specified as a non-selected commonelectrode by the semiconductor device for touch 7.

In FIG. 15, operations in the signal line precharge period and thedisplay period are the same as those described with reference to FIG.12, and thus the description thereof is omitted.

In the touch detection period, the semiconductor device for driver DDICsets both of the selection signals SEL1 and SEL2 to the high level.Accordingly, the switches S11 and S12 shown in FIG. 14 are both turnedon. Also, the control signal VCOMSEL is set to the high level.

When the touch detection period is the touch detection period (selectedcommon electrode), the semiconductor device for touch 7 changes thevoltage of the selection signal TP(0) periodically. Since the controlsignal VCOMSEL is at a high level, the 2-input AND circuit ND2 outputsan inverted signal of the selection signal TP(0) as the switch controlsignal SW4_C. Accordingly, as shown in FIG. 15D and FIG. 15E, the switchcontrol signal SW3_C changes in phase with the selection signal TP(0)and the switch control signal SW4_C changes in reversed phase with theselection signal TP(0). Accordingly, the fourth switches (S80 to S83)and the fifth switches (S90 to S93) are alternately turned on. Sinceboth of the selection signals SEL1 and SEL2 are at a high level, thesignal line SL(0) is connected to the terminals SP11 to SP16 by the unitsignal line selector 6(0). Also, since the control signal VCOMSEL is ata high level, the common electrode TL(0) is connected to the terminalsSP11 to SP16 by the unit switching circuit 100(0).

Accordingly, in the touch detection period (selected), the commonelectrode TL(0) and the signal line SL(0) are alternately connected tothe first voltage wire 1300 and the second voltage wire 700 and thevoltages thereof periodically change in synchronization with the voltagechange of the selection signal TP(0).

Also, the voltage change in the signal line SL(0) is supplied to thesignal wire 800 via the switch circuit SW4. With the voltage change inthe signal wire 800, the switches S20 to S23 and the switches S30 to S33in the first unit drive electrode driver 12-1(0) are alternately turnedon. As a result, the common electrode TL(0) is alternately connected tothe first voltage wire 1300 and the second voltage wire 700 also in thefirst unit drive electrode circuit UCG1(0).

Accordingly, the first voltage TPH and the second voltage VCOMDC arealternately supplied to the drive electrode TL(0) from the both endsthereof and the voltage thereof changes. Accordingly, as described withreference to FIG. 2, whether or not the neighborhood of the commonelectrode TL(0) is touched can be detected.

Meanwhile, when the touch detection period is the touch detection period(non-selected common electrode), the semiconductor device for touch 7sets the selection signal TP(0) to the low level and sets the controlsignal VCOMSEL to the high level as shown in FIG. 15C and FIG. 15B.Since the selection signal TP(0) is at a low level, the 2-input ANDcircuit ND2 outputs a high-level inverted signal obtained by invertingthe phase of the selection signal TP(0) as the switch control signalSW4_C. Accordingly, the common electrode TL(0) and the signal line SL(0)are connected to the second voltage wire 700 via the fifth switches (S90to S93) and the second voltage VCOMDC is supplied to the commonelectrode TL(0) and the signal line SL(0). The voltage of the signalline SL(0) at this time is supplied to the signal wire 800 via theswitch circuit SW4. Since the voltage of the signal wire 800 becomes thesecond voltage VCOMDC corresponding to the ground voltage, the switchesS30 to S33 in the first unit drive electrode driver 12-1(0) are turnedon. As a result, the common electrode TL(0) is connected to the secondvoltage wire 700 via the switches S30 to S33 and the second voltageVCOMDC is supplied.

Accordingly, when the common electrode TL(0) is specified as anon-selected common electrode, the second voltage VCOMDC correspondingto the ground voltage is supplied from both ends thereof and the voltagethereof is fixed to the second voltage VCOMDC. Since the fixed voltage(VCOMDC) is supplied, the voltage of a detection signal does not changeeven if the neighborhood of the common electrode TL(0) is touched, andthe presence or absence of a touch is not detected.

The common electrode TL(0), the first unit drive electrode circuitUCG1(0) and the second unit drive electrode circuit UCG2(0) have beendescribed as a representative example, but the configuration andoperation are the same also in the remaining common electrodes TL(1) toTL(p), first unit drive electrode circuits UCG1(1) to UCG1(p) and secondunit drive electrode circuits UCG2(1) to UCG2(p).

In the third embodiment, the common electrodes TL(0) to TL(p) are drivenby both of the first drive electrode circuit CGW1 and the second driveelectrode circuit CGW2 arranged along the short sides 2-U and 2-D of theliquid crystal panel 2. Thus, the common electrodes can be driven evenif driving ability of each of the first drive electrode circuit CGW1 andthe second drive electrode circuit CGW2 is decreased, so that the lowerand upper edge frames of the liquid crystal panel 2 can be madenarrower. Also, by using the signal line that transmits an image signalin the display period as the control line serving as the wire thattransmits the selection signal from the second drive electrode circuitCGW2 to the first drive electrode circuit CGW1 in the touch detectionperiod, the increase in size of the lateral edge frame of the displaypanel 2 can be suppressed.

In FIG. 13 to FIG. 15, the example in which the signal lines SL(0)corresponding to the common electrode TL(0), that is, the signal linesSL(0)0(R), SL(0)0(G), SL(0)0(B) and SL(0)2(B) in FIG. 14 are used ascontrol lines has been described, but the present embodiment is notlimited to this. At least one signal line of the plurality of signallines corresponding to one common electrode may be used as a controlline. However, by using the plurality of signal lines as control lines,the delay of the selection signal can be reduced.

In the range of an idea of the present invention, a person skilled inthe art can conceive various modifications and alterations and it shouldbe understood that such modifications and alterations belong to thescope of the present invention.

For example, embodiments obtained by the addition, deletion or designchange of elements or the addition, omission or condition change ofsteps made for each of the above-described embodiments by a personskilled in the art are included in the scope of the present invention aslong as they include the gist of the present invention.

In the embodiments, for example, the case in which the common electrodesTL(0) to TL(p) and the signal lines SL(0) to SL(p) extend in the columndirection and are arranged in the row direction has been described, butthe row direction and the column direction change depending on theviewpoint. Specifically, the case in which the viewpoint is changed andthe common electrodes TL(0) to TL(p) and the signal lines SL(0) to SL(p)extend in the row direction and are arranged in the column direction isalso included in the scope of the present invention. Further, in FIG.14, the P-type MOSFET TP2 does not have to be provided.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A display device comprising: apixel array including a plurality of pixels arranged in a matrix formand having a first side parallel to a row and a second side opposite tothe first side; a plurality of scanning lines arranged in each row ofthe pixel array to supply a scanning signal to the plurality of pixelsarranged in a corresponding row; a plurality of signal lines arranged ineach column of the pixel array to supply an image signal to theplurality of pixels arranged in a corresponding column; a plurality ofdrive electrodes which are arranged in a column of the pixel array andto which a drive signal to detect an external proximate object issupplied; and a first drive electrode circuit which is arranged alongthe first side of the pixel array and connected to a plurality ofcontrol lines and the plurality of drive electrodes arranged in thepixel array and supplies the drive signal to, among the plurality ofdrive electrodes, the drive electrode specified by a selection signalsupplied via the plurality of control lines.
 2. The display deviceaccording to claim 1, wherein at least some of the plurality of signallines are the plurality of control lines.
 3. The display deviceaccording to claim 2, further comprising: a signal line circuit arrangedalong the second side of the pixel array and connected to the pluralityof signal lines, wherein the signal line circuit supplies the imagesignal to the plurality of signal lines when an image is displayed inthe pixel array.
 4. The display device according to claim 3, furthercomprising: a touch control device which forms the selection signalspecifying the drive electrode from the plurality of drive electrodeswhen the external proximate object is detected.
 5. The display deviceaccording to claim 2, further comprising: a second drive electrodecircuit arranged along the second side of the pixel array and connectedto the plurality of drive electrodes, wherein the second drive electrodecircuit supplies the drive signal to, among the plurality of driveelectrodes, the same drive electrode as the drive electrode to which thedrive signal is supplied from the first drive electrode circuit.
 6. Thedisplay device according to claim 5, further comprising: a signal linecircuit arranged along the second side of the pixel array and connectedto the plurality of signal lines, wherein the signal line circuitsupplies the image signal to the plurality of signal lines when an imageis displayed in the pixel array.
 7. The display device according toclaim 6, wherein the first drive electrode circuit includes: a drivecircuit; and a separation circuit which is provided between the drivecircuit and the signal lines serving as the plurality of control linesand electrically separates the drive circuit and the signal linesserving as the plurality of control lines when the image is displayed inthe pixel array, and the drive circuit supplies the drive signal whenconnected to the plurality of control lines.
 8. The display deviceaccording to claim 7, wherein the drive signal output from the seconddrive electrode circuit is supplied to the first drive electrode circuitas the selection signal via the signal lines serving as the plurality ofcontrol lines.
 9. The display device according to claim 8, furthercomprising: a touch control device that forms the selection signalspecifying the drive electrode from the plurality of drive electrodeswhen the external proximate object is detected, wherein the second driveelectrode circuit outputs the drive signal based on the selection signalformed by the touch control device.
 10. The display device according toclaim 7, further comprising: a touch control device that forms theselection signal specifying the drive electrode from the plurality ofdrive electrodes when the external proximate object is detected, whereineach of the first drive electrode circuit and the second drive electrodecircuit supplies the drive signal to the drive electrode specified bythe selection signal formed by the touch control device.
 11. The displaydevice according to claim 10, wherein the touch control device sets asignal whose voltage changes periodically as the selection signalcorresponding to the drive electrode to be specified among the pluralityof drive electrodes, and each of the first drive electrode circuit andthe second drive electrode circuit alternately connects the driveelectrode to be specified to a first voltage and a second voltage insynchronization with the selection signal whose voltage changesperiodically.
 12. The display device according to claim 10, wherein thetouch control device sets a signal having a predetermined voltage as theselection signal corresponding to the drive electrode to be specifiedamong the plurality of drive electrodes, and when the signal having thepredetermined voltage is received as the selection signal, each of thefirst drive electrode circuit and the second drive electrode circuitsupplies a signal whose voltage changes periodically to the driveelectrode to be specified as the drive signal.
 13. The display deviceaccording to claim 11, wherein the touch control device is asemiconductor device and the selection signal is formed based onselection information supplied to an external terminal of thesemiconductor device.
 14. The display device according to claim 2,wherein the selection signal is supplied to the plurality of controllines in a touch detection period that is different from a displayperiod in which an image is displayed.
 15. The display device accordingto claim 12, wherein the touch control device is a semiconductor deviceand the selection signal is formed based on selection informationsupplied to an external terminal of the semiconductor device.